daohang fenxiangbox searchbox qikanlogonew daohangnew searchboxnew navrightzone footerzone jigouxiangqing
1111 - 2222

Chinese Journal of Rare Metals

More ↓
0 English Journals
0 Chinese Journals
0 Articles
1 Special Collections
Journals
View All Journals→

Recommended Articles

Enhancement of Hardness, Wear, and Corrosion Resistance in Ti-6Al-4V Alloy through Multi-Layer Laser Cladding of TiZrNbCrCo High Entropy Alloy Coatings Enhancement of Hardness, Wear, and Corrosion Resistance in Ti-6Al-4V Alloy through Multi-Layer Laser Cladding of TiZrNbCrCo High Entropy Alloy Coatings

Given the challenges posed by the low hardness and inadequate wear resistance of Ti-6Al-4V alloy, this research aimed to explore an innovative solution by employing the laser cladding technique to develop high-entropy alloy(HEA)coatings composed of TiZrNbCrCo on the alloy's surface. The primary objectives were to investigate the effects of varying the number of cladding layers on the elemental composition and to assess how these variations influenced the phase constitution, microstructure, microhardness, wear, and electrochemical properties of HEA coatings. To predict the phase composition of the solid solution phases in HEA coatings with different layer numbers, empirical thermophysical parameters were utilized. The methodology encompassed a detailed experimental setup where the laser cladding process was meticulously optimized to fabricate coatings with varying numbers of layers. This approach enabled the controlled manipulation of the dilution rate and elemental distribution within the coatings, thereby allowing for a comprehensive analysis of the resulting phase and microstructural characteristics. The coatings were systematically analyzed using X-ray diffraction(XRD)to identify their phase compositions and scanning electron microscopy to elucidate their microstructures. Microhardness measurements were conducted to evaluate the mechanical enhancements, while wear tests were performed to assess the wear resistance of the coatings. Furthermore, electrochemical tests in a 3.5%NaCl solution were carried out to determine the coatings' corrosion resistance. The results revealed that all coatings, exhibited a consistent phase composition, predominantly featuring a body-centered cubic (bcc) structured solid solution phase. This phase was characterized by dendrites rich in Nb and inter-dendrites rich in Co. It was observed that an increase in the number of cladding layers led to a decrease in the dilution rate, which in turn facilitated the formation of petal-like Laves phases enriched in Co and Zr, along with α-Ti precipitates enriched in Zr. Remarkably, the average microhardness of the coatings reached HV0.1747.7, approximately 2.33 times that of the substrate. This significant enhancement in microhardness translated to a reduction in wear volume by 68.6% compared to the substrate. The optimal corrosion resistance was achieved with a two-layer configuration, which exhibited the lowest self-corrosion current (6.46×10−6 A·cm−2) a larger self-corrosion potential (-0.286 V), and the lowest corrosion rate, indicating a substantial improvement in corrosion resistance. The conclusion drawn from this study highlighted the critical role of laser cladding parameters in influencing the microstructural and compositional characteristics of HEA coatings. The enhancement in mechanical and chemical properties could be attributed to the strategic manipulation of the number of cladding layers, which optimized the microstructural features such as the distribution of Laves phases and α-Ti precipitates. Moreover, this research contributed to the broader academic discourse by elucidating the relationship between laser cladding parameters, microstructural evolution, and the resulting properties of HEA coatings. In summary, this comprehensive investigation into the development and characterization of TiZrNbCrCo high-entropy alloy coatings on Ti-6Al-4V alloy surfaces provided a promising approach for addressing the limitations of conventional titanium alloys. The research outcomes not only demonstrated the feasibility of significantly enhancing the hardness, wear, and corrosion resistance of Ti-6Al-4V alloys through laser cladded HEA coatings but also opened up opportunities for using high-entropy alloys in surface engineering to meet the needs of modern industries.

Research Progress on Doping Modification of High-Capacity Silicon-Based Anode Materials Research Progress on Doping Modification of High-Capacity Silicon-Based Anode Materials

Silicon(Si)-based anodes are widely recognized as the most promising alternatives to conventional graphite anodes for lithium-ion batteries(LIBs), owing to their ultrahigh theoretical specific capacity(4200 mAh·g-1), lowlithiation potential, abundant crustal reserves, low toxicity, and cost-effectiveness. However, their large-scale commercialization is severely hindered by two intrinsic challenges:1) drastic volume expansion(>300%)during lithiation/delithiation, which induces particle pulverization, electrode integrity degradation, and continuous rupture/reformation of the solid electrolyte interphase(SEI)films, thereby causing irreversible lithium-ion consumption; 2) extremely low intrinsic electrical conductivity(1×10-4 S·cm-1), which restricts ion/electron transport kinetics and thus degrades rate capability.To address these issues, early research efforts focused on nano-engineering of Si and the development of Si-based composites. Nanostructured Si can partially alleviate mechanical fracture by accommodating strain through size-dependent deformation mechanisms; however, it tends to agglomerate during prolonged cycling and exhibits excessive side reactions with the electrolyte, reducing the initial Coulombic efficiency(ICE)and cycling lifespan. Si/carbon(Si/C)composites design, which take advantage of the high electrical conductivity, chemical stability, and mechanical flexibility of carbon matrices, have emerged as a primary route toward commercialization. Nevertheless, challenges related to the inherently low conductivity of Si and inadequate interfacial bonding between Si and carbon remain unresolved. Against this backdrop, this review emphasized doping modification as a fundamental strategy to enhance the electrochemical performance of Si-based anodes. Starting from the lithium storage mechanism of Si—which stored lithium via an alloying/dealloying reaction to form various Li-Si alloys, with a theoretical maximum lithiation phase of Li22Si5 accommodating 4.4 Li atoms per Si atom—and its core limitations, we systematically analyzed the regulation mechanisms and functional effects of different doping approaches. These were categorized into three types:non-metallic (heteroatom) doping, metallic doping, and multi-element co-doping. Non-metallic doping(e.g., with B, P, N, or S)effectively modulated the electronic structure of Si-based materials, improved Li+ transport pathways, enhanced electronic conductivity, and promoted the formation of a more stable SEI layer. Metallic doping was subdivided into two categories:electrochemically inactive metals(e.g., Fe, Ti), which enhanced electrical conduction and provided mechanical reinforcement to alleviate volume expansion, and electrochemically active metals(e.g., Mg, Ge), which contributed additional capacity and helped accommodate volume expansion through synergistic alloying behavior. Multi-element co-doping(including non-metal/non-metal and metal/non-metal combinations)achieved synergistic optimization of multiple physicochemical properties, thus further enhancing conductivity, structural stability, and fast-charging performance. Finally, this review outlined future perspectives for doping modification technologies in Si-based anodes, including the exploration of novel co-doping systems to simultaneously address conductivity, volume expansion, and SEI stability; the optimization of doping processes for precise control over elemental distribution and concentration; and the integration of in-situ characterization techniques to deepen the understanding of the influence of doping elements on the lithium storage mechanism. This review aimed to provide fundamental theoretical insights and practical technical guidance for the development of high-energy-density and fast-charging Si-based anode materials, thereby accelerating their commercial adoption.

Research on Safety Strategy on New Materials Industrial Development Research on Safety Strategy on New Materials Industrial Development

As a fundamental pillar for fostering new quality productive forces, constructing a modern industrial system and safeguarding national comprehensive security, the new materials industry underpins the core competitiveness of high-end manufacturing and cutting-edge technologies. Today's global industrial landscape is undergoing profound restructuring driven by four pivotal forces:intensifying geopolitical competition, worldwide carbon peaking and carbon neutrality transitions, in-depth integration of digital and intelligent technologies, and targeted iteration of materials spurred by diverse downstream application scenarios. In parallel, artificial intelligence, big data and high-throughput computing are revolutionizing the traditional trial-and-error R&D paradigm of materials science, enabling data-driven material screening, inverse structural design and intelligent process optimization to drastically cut research cycles and experimental costs. This paper systematically sorted out the opportunities and structural risks confronting the global new materials industry, and thoroughly reviewed the strategic arrangements rolled out by the United States, the European Union, Germany, the United Kingdom, Japan and Russia in 2025 and 2026. U.S. tied new materials closely to national defense and technological security, launching special programs including Crystal Palace and Carbon Crunch for military advanced materials, and consolidated independent supply chains for semiconductor materials through the CHIPS and Science Act, alongside initiatives to supervise critical mineral resources and apply AI to accelerate material innovation. EU centered its strategy on European strategic autonomy and green transformation, advancing the Advanced Materials Act and the Critical Raw Materials Act to diversify mineral supply, developed circular materials and set global green trade standards. Germany, UK, Japan and Russia had also introduced targeted national plans respectively, focusing on technological sovereignty, digitalized material R&D, military-civilian integrated innovation, rare earth recycling and import substitution amid geopolitical sanctions. After years of policy support and technological accumulation, China had achieved remarkable breakthroughs in lithium battery materials, rare earth functional materials and general carbon fibers, with a batch of national key innovation platforms and specialized sophisticated enterprises cultivated. Nevertheless, prominent internal and external vulnerabilities persisted. Externally, fierce global technological competition and restrictive trade policies created severe "bottleneck" risks, as high-end photoresists, single-crystal superalloys, core manufacturing equipment and other strategic materials still relied heavily on imports, and China lacked sufficient discourse power in formulating international material standards. Targeting six core strategic fields with prominent security risks, this study proposed targeted development frameworks for self-reliant industrial construction. For micro-nano electronic manufacturing, it highlighted localized substitution of bottleneck materials such as photoresists and electronic specialty gases, alongside R&D of low-dielectric materials and wide-bandgap semiconductor supporting materials to match advanced packaging and high-performance chip demands. For aerospace, it advocated full-chain independent manufacturing of high-performance carbon fibers, single-crystal superalloys and ceramic matrix composites to satisfy extreme service conditions of hypersonic vehicles and reusable rockets. For robotics and sensors, priorities covered lightweight structural alloys, rare earth permanent magnets and flexible sensing materials to support bionic robots and precision perception systems. In advanced nuclear energy, the paper stressed breakthroughs in radiation-resistant cladding materials and low-activation structural alloys to support fourth-generation reactors and space nuclear power sources. For marine engineering equipment, corrosion-resistant high-strength steel and deep-sea functional materials were key to advancing polar vessels and offshore renewable energy infrastructure. To systematically resolve industrial security challenges, this paper put forward multi-dimensional countermeasures covering five core dimensions. First, innovation-driven development shall be strengthened via the new whole-of-nation system to tackle generic bottleneck technologies, improve the commercialization system of scientific achievements and optimize intellectual property management for strategic materials. Second, supply chain resilience would be reinforced through domestic mineral exploration, diversified cross-border resource cooperation, national strategic mineral reserves and digital risk early warning platforms. Third, an integrated standard system aligned with international norms shall be established to fill standard gaps in high-end materials and implement full-lifecycle quality traceability management. Fourth, a multi-level talent training matrix would be optimized through industry-university-research integration, performance evaluation reforms and market-oriented incentive mechanisms to address talent shortages. Fifth, the industrial ecosystem would be upgraded through targeted policy support for industrial clusters, intelligent production line transformation and low-carbon circular manufacturing to advance high-end, intelligent and green development simultaneously. In summary, the safety of the new materials industry constituted an indispensable foundation of national industrial and scientific security. Faced with sweeping global industrial reshuffling and fierce international competition, China must advance coordinated upgrades across technological innovation, supply chain robustness, standardization, talent cultivation and industrial ecology. The conclusions and suggestions of this research could provide theoretical reference and practical guidance for constructing an independent, controllable, safe and efficient new materials industrial system, consolidating the bottom line of national scientific and industrial security, and fueling the steady growth of new quality productive forces and the advancement of new industrialization.

Enhancement of Hardness, Wear, and Corrosion Resistance in Ti-6Al-4V Alloy through Multi-Layer Laser Cladding of TiZrNbCrCo High Entropy Alloy Coatings Enhancement of Hardness, Wear, and Corrosion Resistance in Ti-6Al-4V Alloy through Multi-Layer Laser Cladding of TiZrNbCrCo High Entropy Alloy Coatings

Given the challenges posed by the low hardness and inadequate wear resistance of Ti-6Al-4V alloy, this research aimed to explore an innovative solution by employing the laser cladding technique to develop high-entropy alloy(HEA)coatings composed of TiZrNbCrCo on the alloy's surface. The primary objectives were to investigate the effects of varying the number of cladding layers on the elemental composition and to assess how these variations influenced the phase constitution, microstructure, microhardness, wear, and electrochemical properties of HEA coatings. To predict the phase composition of the solid solution phases in HEA coatings with different layer numbers, empirical thermophysical parameters were utilized. The methodology encompassed a detailed experimental setup where the laser cladding process was meticulously optimized to fabricate coatings with varying numbers of layers. This approach enabled the controlled manipulation of the dilution rate and elemental distribution within the coatings, thereby allowing for a comprehensive analysis of the resulting phase and microstructural characteristics. The coatings were systematically analyzed using X-ray diffraction(XRD)to identify their phase compositions and scanning electron microscopy to elucidate their microstructures. Microhardness measurements were conducted to evaluate the mechanical enhancements, while wear tests were performed to assess the wear resistance of the coatings. Furthermore, electrochemical tests in a 3.5%NaCl solution were carried out to determine the coatings' corrosion resistance. The results revealed that all coatings, exhibited a consistent phase composition, predominantly featuring a body-centered cubic (bcc) structured solid solution phase. This phase was characterized by dendrites rich in Nb and inter-dendrites rich in Co. It was observed that an increase in the number of cladding layers led to a decrease in the dilution rate, which in turn facilitated the formation of petal-like Laves phases enriched in Co and Zr, along with α-Ti precipitates enriched in Zr. Remarkably, the average microhardness of the coatings reached HV0.1747.7, approximately 2.33 times that of the substrate. This significant enhancement in microhardness translated to a reduction in wear volume by 68.6% compared to the substrate. The optimal corrosion resistance was achieved with a two-layer configuration, which exhibited the lowest self-corrosion current (6.46×10−6 A·cm−2) a larger self-corrosion potential (-0.286 V), and the lowest corrosion rate, indicating a substantial improvement in corrosion resistance. The conclusion drawn from this study highlighted the critical role of laser cladding parameters in influencing the microstructural and compositional characteristics of HEA coatings. The enhancement in mechanical and chemical properties could be attributed to the strategic manipulation of the number of cladding layers, which optimized the microstructural features such as the distribution of Laves phases and α-Ti precipitates. Moreover, this research contributed to the broader academic discourse by elucidating the relationship between laser cladding parameters, microstructural evolution, and the resulting properties of HEA coatings. In summary, this comprehensive investigation into the development and characterization of TiZrNbCrCo high-entropy alloy coatings on Ti-6Al-4V alloy surfaces provided a promising approach for addressing the limitations of conventional titanium alloys. The research outcomes not only demonstrated the feasibility of significantly enhancing the hardness, wear, and corrosion resistance of Ti-6Al-4V alloys through laser cladded HEA coatings but also opened up opportunities for using high-entropy alloys in surface engineering to meet the needs of modern industries.

Research Progress on Doping Modification of High-Capacity Silicon-Based Anode Materials Research Progress on Doping Modification of High-Capacity Silicon-Based Anode Materials

Silicon(Si)-based anodes are widely recognized as the most promising alternatives to conventional graphite anodes for lithium-ion batteries(LIBs), owing to their ultrahigh theoretical specific capacity(4200 mAh·g-1), lowlithiation potential, abundant crustal reserves, low toxicity, and cost-effectiveness. However, their large-scale commercialization is severely hindered by two intrinsic challenges:1) drastic volume expansion(>300%)during lithiation/delithiation, which induces particle pulverization, electrode integrity degradation, and continuous rupture/reformation of the solid electrolyte interphase(SEI)films, thereby causing irreversible lithium-ion consumption; 2) extremely low intrinsic electrical conductivity(1×10-4 S·cm-1), which restricts ion/electron transport kinetics and thus degrades rate capability.To address these issues, early research efforts focused on nano-engineering of Si and the development of Si-based composites. Nanostructured Si can partially alleviate mechanical fracture by accommodating strain through size-dependent deformation mechanisms; however, it tends to agglomerate during prolonged cycling and exhibits excessive side reactions with the electrolyte, reducing the initial Coulombic efficiency(ICE)and cycling lifespan. Si/carbon(Si/C)composites design, which take advantage of the high electrical conductivity, chemical stability, and mechanical flexibility of carbon matrices, have emerged as a primary route toward commercialization. Nevertheless, challenges related to the inherently low conductivity of Si and inadequate interfacial bonding between Si and carbon remain unresolved. Against this backdrop, this review emphasized doping modification as a fundamental strategy to enhance the electrochemical performance of Si-based anodes. Starting from the lithium storage mechanism of Si—which stored lithium via an alloying/dealloying reaction to form various Li-Si alloys, with a theoretical maximum lithiation phase of Li22Si5 accommodating 4.4 Li atoms per Si atom—and its core limitations, we systematically analyzed the regulation mechanisms and functional effects of different doping approaches. These were categorized into three types:non-metallic (heteroatom) doping, metallic doping, and multi-element co-doping. Non-metallic doping(e.g., with B, P, N, or S)effectively modulated the electronic structure of Si-based materials, improved Li+ transport pathways, enhanced electronic conductivity, and promoted the formation of a more stable SEI layer. Metallic doping was subdivided into two categories:electrochemically inactive metals(e.g., Fe, Ti), which enhanced electrical conduction and provided mechanical reinforcement to alleviate volume expansion, and electrochemically active metals(e.g., Mg, Ge), which contributed additional capacity and helped accommodate volume expansion through synergistic alloying behavior. Multi-element co-doping(including non-metal/non-metal and metal/non-metal combinations)achieved synergistic optimization of multiple physicochemical properties, thus further enhancing conductivity, structural stability, and fast-charging performance. Finally, this review outlined future perspectives for doping modification technologies in Si-based anodes, including the exploration of novel co-doping systems to simultaneously address conductivity, volume expansion, and SEI stability; the optimization of doping processes for precise control over elemental distribution and concentration; and the integration of in-situ characterization techniques to deepen the understanding of the influence of doping elements on the lithium storage mechanism. This review aimed to provide fundamental theoretical insights and practical technical guidance for the development of high-energy-density and fast-charging Si-based anode materials, thereby accelerating their commercial adoption.

Research on Safety Strategy on New Materials Industrial Development Research on Safety Strategy on New Materials Industrial Development

As a fundamental pillar for fostering new quality productive forces, constructing a modern industrial system and safeguarding national comprehensive security, the new materials industry underpins the core competitiveness of high-end manufacturing and cutting-edge technologies. Today's global industrial landscape is undergoing profound restructuring driven by four pivotal forces:intensifying geopolitical competition, worldwide carbon peaking and carbon neutrality transitions, in-depth integration of digital and intelligent technologies, and targeted iteration of materials spurred by diverse downstream application scenarios. In parallel, artificial intelligence, big data and high-throughput computing are revolutionizing the traditional trial-and-error R&D paradigm of materials science, enabling data-driven material screening, inverse structural design and intelligent process optimization to drastically cut research cycles and experimental costs. This paper systematically sorted out the opportunities and structural risks confronting the global new materials industry, and thoroughly reviewed the strategic arrangements rolled out by the United States, the European Union, Germany, the United Kingdom, Japan and Russia in 2025 and 2026. U.S. tied new materials closely to national defense and technological security, launching special programs including Crystal Palace and Carbon Crunch for military advanced materials, and consolidated independent supply chains for semiconductor materials through the CHIPS and Science Act, alongside initiatives to supervise critical mineral resources and apply AI to accelerate material innovation. EU centered its strategy on European strategic autonomy and green transformation, advancing the Advanced Materials Act and the Critical Raw Materials Act to diversify mineral supply, developed circular materials and set global green trade standards. Germany, UK, Japan and Russia had also introduced targeted national plans respectively, focusing on technological sovereignty, digitalized material R&D, military-civilian integrated innovation, rare earth recycling and import substitution amid geopolitical sanctions. After years of policy support and technological accumulation, China had achieved remarkable breakthroughs in lithium battery materials, rare earth functional materials and general carbon fibers, with a batch of national key innovation platforms and specialized sophisticated enterprises cultivated. Nevertheless, prominent internal and external vulnerabilities persisted. Externally, fierce global technological competition and restrictive trade policies created severe "bottleneck" risks, as high-end photoresists, single-crystal superalloys, core manufacturing equipment and other strategic materials still relied heavily on imports, and China lacked sufficient discourse power in formulating international material standards. Targeting six core strategic fields with prominent security risks, this study proposed targeted development frameworks for self-reliant industrial construction. For micro-nano electronic manufacturing, it highlighted localized substitution of bottleneck materials such as photoresists and electronic specialty gases, alongside R&D of low-dielectric materials and wide-bandgap semiconductor supporting materials to match advanced packaging and high-performance chip demands. For aerospace, it advocated full-chain independent manufacturing of high-performance carbon fibers, single-crystal superalloys and ceramic matrix composites to satisfy extreme service conditions of hypersonic vehicles and reusable rockets. For robotics and sensors, priorities covered lightweight structural alloys, rare earth permanent magnets and flexible sensing materials to support bionic robots and precision perception systems. In advanced nuclear energy, the paper stressed breakthroughs in radiation-resistant cladding materials and low-activation structural alloys to support fourth-generation reactors and space nuclear power sources. For marine engineering equipment, corrosion-resistant high-strength steel and deep-sea functional materials were key to advancing polar vessels and offshore renewable energy infrastructure. To systematically resolve industrial security challenges, this paper put forward multi-dimensional countermeasures covering five core dimensions. First, innovation-driven development shall be strengthened via the new whole-of-nation system to tackle generic bottleneck technologies, improve the commercialization system of scientific achievements and optimize intellectual property management for strategic materials. Second, supply chain resilience would be reinforced through domestic mineral exploration, diversified cross-border resource cooperation, national strategic mineral reserves and digital risk early warning platforms. Third, an integrated standard system aligned with international norms shall be established to fill standard gaps in high-end materials and implement full-lifecycle quality traceability management. Fourth, a multi-level talent training matrix would be optimized through industry-university-research integration, performance evaluation reforms and market-oriented incentive mechanisms to address talent shortages. Fifth, the industrial ecosystem would be upgraded through targeted policy support for industrial clusters, intelligent production line transformation and low-carbon circular manufacturing to advance high-end, intelligent and green development simultaneously. In summary, the safety of the new materials industry constituted an indispensable foundation of national industrial and scientific security. Faced with sweeping global industrial reshuffling and fierce international competition, China must advance coordinated upgrades across technological innovation, supply chain robustness, standardization, talent cultivation and industrial ecology. The conclusions and suggestions of this research could provide theoretical reference and practical guidance for constructing an independent, controllable, safe and efficient new materials industrial system, consolidating the bottom line of national scientific and industrial security, and fueling the steady growth of new quality productive forces and the advancement of new industrialization.

Short-Range Ordering of Disordered Rock Salt Phase Li1.1Mn0.8Ti0.1O1.9F0.1 Short-Range Ordering of Disordered Rock Salt Phase Li1.1Mn0.8Ti0.1O1.9F0.1

Lithium-excess disordered rock-salt (DRX) materials have emerged as promising cathode candidates owing to their high capacity and energy density. Although short-range ordering (SRO) has been reported in DRX material Li1.16Ti0.37Ni0.37Nb0.10O2,quantitative analysis of its real-space structural origin remains scarce. Therefore,this paper mainly characterized Li1.1Mn0.8Ti0.1O1.9F0.1 using spherical aberration-corrected transmission electron microscopy (TEM). Through a series of tilting experiments,the distribution of diffuse scattering bands was identified. Quantitative analysis of atomic-resolution images confirmed that these diffuse bands in electron diffraction arised mainly from intensity variations within the transition-metal (TM) cation columns,indicating that SRO originated from the specific distribution of cations. For comparison,Li1.05Mn0.85Ti0.1O2 without F was also designed,and it was found that the ordering was significantly enhanced. These results suggested that fluorination might correlate with the improved electrochemical performance via its influence on SRO. The arrangement of disordered cations and the concentration of vacancies directly affected Li percolation pathways and consequently the electrochemical behavior of DRX anodes. Li1.05Mn0.85Ti0.1O2 (LMTO) and Li1.1Mn0.8Ti0.1O1.9F0.1 (LMTOF) were synthesized by weighing stoichiometric amounts of Li2CO3,Mn2O3,TiO2,and LiF,and mixing them in a ZrO2 ball-milling jar. The mixture was ball-milled at 600 r·min−1 for 6 h,then heated in a tube furnace under an inert atmosphere at a rate of 3 ℃·min−1 to 1100 ℃,held for 20 min,and cooled naturally to room temperature. To avoid Ga+ beam damage during focused ion beam (FIB) sampling,atomic-resolution images were obtained from particles directly dispersed onto microgrids via ultrasonication. For TEM observation,powder samples were ultrasonically dispersed in dimethyl carbonate and deposited onto carbon films or grids. Selected-area diffraction patterns were acquired using a JEOL JEM-F200 thermal field-emission TEM,with the beam positioned at thin particle edges. High-angle annular dark-field scanning TEM (HAADF-STEM) images were obtained using a JEOL JEM-ARM200F cold field-emission microscope equipped with a spherical-aberration corrector,operated at 200 kV with a collection angle of 50~200 mrad. Fast Fourier transform (FFT) patterns showing clear diffuse bands were processed using Calatom software,involving filtering,Fourier transform,and inverse Fourier transform of HAADF-STEM images. Periodic structures yield sharp Bragg spots in Fourier space,while diffuse scattering was distributed throughout reciprocal space. To extract triple-periodic structural information,appropriate filtering windows were applied around major Bragg reflections before inverse Fourier transformation. Calatom analysis showed that diffuse bands in experimental FFT patterns correspond to variations in TM column intensity rather than positional disorder. In Li1.1Mn0.8Ti0.1O1.9F0.1,SRO primarily resulted from intensity variations of Ti/Mn cation columns,likely influenced by Li site occupancy. Filtering that retains superstructure information in FFT led to periodic strong-weak intensity modulation of atomic columns,whereas filtering only the main reflections yield homogeneous intensity. Since HAADF intensity scales with atomic number,and only Ti and Mn were visible along [001] zone axis,the observed superstructure in Li1.1Mn0.8Ti0.1O2 could be attributed to SRO similar to that in the fluorinated sample. This implied that the superstructure was related to TM column intensity variations associated with ordered Li occupancy. In Li1.1Mn0.8Ti0.1O2,enhanced ordering was observed,with elongated superstructure reflections appearing at wave vectors q1=a*–0.5b*,q2=0.5a*–0.5b*,and q3=0.5a*–b*,indicating cation ordering. These results suggested that F-doping improved capacity retention by reducing cation (including Li) ordering. The SRO of TM cations within the disordered lattice significantly influenced Li percolation channels during cycling. Therefore,understanding DRX structures at the atomic scale could guide the design and optimization of high-performance Li-excess disordered rock-salt cathodes.

Research Progress on Doping Modification of High-Capacity Silicon-Based Anode Materials Research Progress on Doping Modification of High-Capacity Silicon-Based Anode Materials

Silicon(Si)-based anodes are widely recognized as the most promising alternatives to conventional graphite anodes for lithium-ion batteries(LIBs), owing to their ultrahigh theoretical specific capacity(4200 mAh·g-1), lowlithiation potential, abundant crustal reserves, low toxicity, and cost-effectiveness. However, their large-scale commercialization is severely hindered by two intrinsic challenges:1) drastic volume expansion(>300%)during lithiation/delithiation, which induces particle pulverization, electrode integrity degradation, and continuous rupture/reformation of the solid electrolyte interphase(SEI)films, thereby causing irreversible lithium-ion consumption; 2) extremely low intrinsic electrical conductivity(1×10-4 S·cm-1), which restricts ion/electron transport kinetics and thus degrades rate capability.To address these issues, early research efforts focused on nano-engineering of Si and the development of Si-based composites. Nanostructured Si can partially alleviate mechanical fracture by accommodating strain through size-dependent deformation mechanisms; however, it tends to agglomerate during prolonged cycling and exhibits excessive side reactions with the electrolyte, reducing the initial Coulombic efficiency(ICE)and cycling lifespan. Si/carbon(Si/C)composites design, which take advantage of the high electrical conductivity, chemical stability, and mechanical flexibility of carbon matrices, have emerged as a primary route toward commercialization. Nevertheless, challenges related to the inherently low conductivity of Si and inadequate interfacial bonding between Si and carbon remain unresolved. Against this backdrop, this review emphasized doping modification as a fundamental strategy to enhance the electrochemical performance of Si-based anodes. Starting from the lithium storage mechanism of Si—which stored lithium via an alloying/dealloying reaction to form various Li-Si alloys, with a theoretical maximum lithiation phase of Li22Si5 accommodating 4.4 Li atoms per Si atom—and its core limitations, we systematically analyzed the regulation mechanisms and functional effects of different doping approaches. These were categorized into three types:non-metallic (heteroatom) doping, metallic doping, and multi-element co-doping. Non-metallic doping(e.g., with B, P, N, or S)effectively modulated the electronic structure of Si-based materials, improved Li+ transport pathways, enhanced electronic conductivity, and promoted the formation of a more stable SEI layer. Metallic doping was subdivided into two categories:electrochemically inactive metals(e.g., Fe, Ti), which enhanced electrical conduction and provided mechanical reinforcement to alleviate volume expansion, and electrochemically active metals(e.g., Mg, Ge), which contributed additional capacity and helped accommodate volume expansion through synergistic alloying behavior. Multi-element co-doping(including non-metal/non-metal and metal/non-metal combinations)achieved synergistic optimization of multiple physicochemical properties, thus further enhancing conductivity, structural stability, and fast-charging performance. Finally, this review outlined future perspectives for doping modification technologies in Si-based anodes, including the exploration of novel co-doping systems to simultaneously address conductivity, volume expansion, and SEI stability; the optimization of doping processes for precise control over elemental distribution and concentration; and the integration of in-situ characterization techniques to deepen the understanding of the influence of doping elements on the lithium storage mechanism. This review aimed to provide fundamental theoretical insights and practical technical guidance for the development of high-energy-density and fast-charging Si-based anode materials, thereby accelerating their commercial adoption.

Enhanced Difluoromethane Gas Sensing Performance of Au/ZnO Nanotree Arrays under Visible Light Pulse Excitement Enhanced Difluoromethane Gas Sensing Performance of Au/ZnO Nanotree Arrays under Visible Light Pulse Excitement

With the development of modern industry and the rise of Internet of Things (IoT) technology,gas sensors are widely employed in many fields,such as industrial production,environmental monitoring,food safety,and healthcare devices,playing important role in promoting industrial intelligence and ensuring human health. Among various types of sensors,resistive chemical sensors based on metal oxide semiconductors (MOS) have been considered be ideal gas sensors due to their low cost,mature technology,and good repeatability. However,some issues such as low sensitivity,long response/recovery time,and poor selectivity still impede further development of gas sensors. According to previous study,increasing specific surface area of sensing material and adding noble metal component were advisable strategies to enhance sensingperformance. Besides,interestingly,hot electrons could be generated through the surface plasmon resonance (SPR) effected of plasmonic materials (such as gold nanoparticles,Au NPs) under visible light illumination. They exhibited the potential to modulate carrier concentration and conductivity properties of the adjacent semiconductor material for further promoting sensingperformance. Motivated by these inspirations,in this study,the Au/ZnO nanotree arrays were prepared on silicon wafer and interdigital electrode substrate by a simple hydrothermal method,and used to detect difluoromethane (R32) gas with an optical enhancement working scheme. By using a variety of characterization methods like scanning electron microscopy (SEM),transmission electron microscopy (TEM),X-ray diffraction (XRD),X-ray photoelectron spectroscopy (XPS),ultraviolet and visible spectrophotometer (UV-vis),fluorescence spectrometer (FS),and atomic force microscope (AFM),the morphological structure,element composition and valence state,photoelectric properties and other concerning physical and chemical properties of the sample were systematically investigated and analyzed. In detail,the results showed that ZnO nanotree arrays grew closely perpendicular to the substrate. The diameter of the stem and branches were about 400 and 60 nm,respectively. Au NPs in an average particle size about 10 nm were uniformly distributed on the surface of ZnO. Energy dispersive spectroscopy (EDS) elemental mapping images confirmed that Zn,O,and Au elements were evenly distributed on ZnO surface. The lattice spacing of 0.26 and 0.24 nm observed by high-resolution TEM correspond to (002) crystal plane of ZnO and (111) crystal plane of Au,respectively. The bright diffraction spots on selected area electron diffraction (SAED) pattern were ascribed to (002) crystal plane of ZnO. XRD pattern showed the as-prepared ZnO and Au NPs match well with hexagonal wurtzite ZnO (JCPDS No. 36-1451) and cubic Au (JCPDS No. 04-0784),respectively. The diffraction peaks at 31.72°,34.42°,36.25°,47.53°,and 56.6° were assigned to (100), (002), (101), (102),and (110) planes of ZnO,respectively. The diffraction peak at 36.61° was assigned to (111) plane of Au. XPS spectra affirmed the chemical valence state of Zn,O and Au elements. The doublet peaks at 1022.3 and 1045.3eV corresponded to Zn2+ species. The doublet peaks at 530.5 and 532.3 eV corresponded to the lattice oxygen (Olat) and defect oxygen (Ov) of ZnO,respectively. The doublet peaks at 83.5 and 87.4 eV proved that Au elements exist in the form of metallic Au0. UV-vis spectrashowedthe light absorption of ZnO nanotree array modified by Au NPs was significantly enhanced in the wavelength range of 500~600 nm due to SPR effected of Au NPs. The band gaps of pure ZnO nanotree array and Au/ZnO nanotree array were accordingly calculated to be 3.17 and 3.09 eV through Tauc formula. The band gap of sample was reduced after modified with Au NPs owing to the regulation of the electron transfer characteristics. The fluorescence spectra showed the photoluminescence (PL) intensity of Au/ZnO nanotree array was decreased in 350~550 nm region compared with pure ZnO nanotree array,indicating that the photogenerated charges of Au/ZnO nanotree array possessed high the separation and transfer efficiency. AFM probe platform was used to image hot electron current that induced by SPR effect of Au NPs. The photocurrent imaging results showed that no obvious currents were detected for pure ZnO nanotree array with or without light irradiation. For Au/ZnO nanotree array,the current value increased by about 1 nA under light irradiation than that of in dark conditions,verifying that Au NPs could induce a large number of hot electrons under light irradiation. The influence of visible light on the resistance values of Au/ZnO nanotree array was also investigated on mini multi-functional probe station. It was found that Au/ZnO nanotree array exhibited outstanding sensitivity and stability to visible light,and short response and recovery time within 2 s. By utilizing the modulation function of hot electrons in the visible light pulse working mode,as well as the contribution from the unique structural merits of nanotree array,Au/ZnO nanotree array-based gas sensor showed a high response value of 6.9,fast response/recovery speed,and excellent selectivity in terms of detecting 1000×10-6 R32. The research results could provide useful theoretical and practical guidance for the design and exploitation of enhanced functional nanostructures and optimized integration of high-performance gas sensors.