Conversion-type electrode materials hold significant promise for potassium-ion batteries(PIBs)due to their high theoretical capacities,yet their practical deployment is hindered by sluggish kinetics and irreversible s...Conversion-type electrode materials hold significant promise for potassium-ion batteries(PIBs)due to their high theoretical capacities,yet their practical deployment is hindered by sluggish kinetics and irreversible structural degradation.To overcome these limitations,we propose a rationally engineered nanoreactor architecture that stabilizes defect-rich MoS_(2)via interlayer incorporation of a carbon monolayer,followed by encapsulation within a nitrogen-doped carbon shell,forming a MoSSe@NC heterostructure.This tailored structure synergistically accelerates both K^(+)diffusion kinetics and electron transfer,enabling unprecedented rate performance(107 mAh g^(-1)at 10 Ag^(-1))and ultralong cyclability(86.5%capacity retention after 1200 cycles at 3 A g^(-1)).Mechanistic insights reveal a distinctive“adsorption-conversion”pathway,where sulfur vacancies on exposed S-Mo-S basal planes act as preferential K^(+)adsorption sites,effectively suppressing parasitic phase transitions during intercalation.In situ X-ray diffraction and transmission electron microscopy corroborate the structural reversibility of the conversion reaction,with the carbon matrix dynamically accommodating strain while preserving electrode integrity.This work not only advances the understanding of defect-driven interfacial chemistry in conversion-type materials but also provides a versatile strategy for designing high-performance anodes in next-generation PIBs through heterostructure engineering.展开更多
The irreversible oxygen redox(OR)in Li-rich layered cathodes leads to severe structural degradation and voltage decay,particularly under harsh operating conditions.Although high-entropy oxides(HEOs)offer enhanced stab...The irreversible oxygen redox(OR)in Li-rich layered cathodes leads to severe structural degradation and voltage decay,particularly under harsh operating conditions.Although high-entropy oxides(HEOs)offer enhanced stability compared to conventional doping modifications,rational element selection for optimizing OR reversibility remains unexplored.Here,we propose an entropy engineering design paradigm for “oxygen-anchoring”,where optimal cation electronegativity(>Mn,1.55)and d(3d/4d)-p orbital hybridization synergistically enhance transition metal–oxygen(TM–O)covalency and stabilize the O2p state.Two high-entropy Li-rich layered oxides:Li_(1.2)Mn_(0.47)Ni_(0.115)Co_(0.115)Mg_(0.02)Ti_(0.02)Al_(0.02)Nb_(0.02)Mo_(0.02)O_(2)(MTANM)and Li_(1.2)Mn_(0.47)Ni_(0.115)Co_(0.115)Mg_(0.02)Ti_(0.02)Cu_(0.02)Nb_(0.02)Mo_(0.02)O_(2)(MTCNM)were synthesized using partial nano-scale precursors and comparatively evaluated.MTCNM exhibits enhanced electrochemical performance and superior oxygen stability compared to MTANM by replacing Al with higher-electronegativity Cu,which possesses improved orbital overlap with oxygen.Both experiments and density functional theory(DFT)calculations demonstrate that element selection changes the covalency of TM–O through altered electronegativity and d orbitals-p orbitals(d-p)hybridization.Further stepwise screening selected the optimal elemental combination Li_(1.2)Mn_(0.47)Ni_(0.115)Co_(0.115)Cr_(0.02)Cu_(0.02)Nb_(0.02)Mo_(0.02)Ru_(0.02)O_(2)(CCNMR),which achieved near 100%capacity retention after 150 cycles at 1 C,50℃,with its voltage decay effectively suppressed.This work establishes a rational element-screening paradigm for entropy-stabilized OR chemistry in high-energy cathodes.展开更多
P3-type manganese-iron-based cathodes with high specific capacity and abundant resource have attracted considerable attention for sodium-ion batteries.However,the long-term cycle stability of P3-type cathodes is still...P3-type manganese-iron-based cathodes with high specific capacity and abundant resource have attracted considerable attention for sodium-ion batteries.However,the long-term cycle stability of P3-type cathodes is still not satisfactory.In this work,we design a new quaternary manganese-iron-based cathode material(P3-Na_(0.54)Mn_(0.64)Fe_(_(0.1)6)Mg_(0.1)Cu_(0.1)O_(2))by Cu substitution.The strong covalent Cu-O bonds improve the structural stability and the reversibility of O redox during charge and discharge processes.Cu substitution also mitigates the structure change with less unit cell volume variation,and improves the Na-ion transport kinetics effectively.As a result,NMFMC delivers much improved cycling stability and rate capability compared with NMFM.It reveals that the charge compensation of NMFMC is mainly contributed by Mn^(3+/4+),Fe^(3+/3.5+)and O_(2-/-)during the charge and discharge processes,and Cu substitution can also enhance the activity and reversibility of Fe redox.This strategy provides a new pathway toward improving the stability and O redox reversibility of P3-type cathode materials for sodium-ion batteries.展开更多
为分析集成三维点云逆向建模方法(integrated 3D point cloud reverse modeling,IPCRM)在建立薄厚型钢构件三维模型时的精度表现,以局部变形角钢为研究对象,利用SfM(structure from motion)-MVS(multi-view stereo)算法建立其三维点云模...为分析集成三维点云逆向建模方法(integrated 3D point cloud reverse modeling,IPCRM)在建立薄厚型钢构件三维模型时的精度表现,以局部变形角钢为研究对象,利用SfM(structure from motion)-MVS(multi-view stereo)算法建立其三维点云模型,借助逆向建模技术生成曲面模型,重点开展了模型精度验证试验.结果表明:各表面形状特征参数的相对误差均在8%以内(吻合度验证);4种角钢模型与实际角钢间无显著性差异(P值,P=0.99),且角钢厚度对模型精度无显著性影响(P值,P=0.95),结论在95%的置信度水平下成立(差异显著性验证).研究结果为后续算法优化及利用此类方法进行合理的钢构件局部变形损伤检测与承载性能评价提供依据.展开更多
基金financially supported by the supported by Shandong Provincial Natural Science Foundation(ZR2024MB108)Taishan Young Scholar Program(tsqn202312312)Excellent Young Scholars of the Shandong Provincial Natural Science Foundation(Overseas)(2023HWYQ-112)。
文摘Conversion-type electrode materials hold significant promise for potassium-ion batteries(PIBs)due to their high theoretical capacities,yet their practical deployment is hindered by sluggish kinetics and irreversible structural degradation.To overcome these limitations,we propose a rationally engineered nanoreactor architecture that stabilizes defect-rich MoS_(2)via interlayer incorporation of a carbon monolayer,followed by encapsulation within a nitrogen-doped carbon shell,forming a MoSSe@NC heterostructure.This tailored structure synergistically accelerates both K^(+)diffusion kinetics and electron transfer,enabling unprecedented rate performance(107 mAh g^(-1)at 10 Ag^(-1))and ultralong cyclability(86.5%capacity retention after 1200 cycles at 3 A g^(-1)).Mechanistic insights reveal a distinctive“adsorption-conversion”pathway,where sulfur vacancies on exposed S-Mo-S basal planes act as preferential K^(+)adsorption sites,effectively suppressing parasitic phase transitions during intercalation.In situ X-ray diffraction and transmission electron microscopy corroborate the structural reversibility of the conversion reaction,with the carbon matrix dynamically accommodating strain while preserving electrode integrity.This work not only advances the understanding of defect-driven interfacial chemistry in conversion-type materials but also provides a versatile strategy for designing high-performance anodes in next-generation PIBs through heterostructure engineering.
基金financially supported by the National Natural Science Foundation of China(no.52172209)the Shenzhen International Cooperative Research Project(GJHZ20240218113607014)。
文摘The irreversible oxygen redox(OR)in Li-rich layered cathodes leads to severe structural degradation and voltage decay,particularly under harsh operating conditions.Although high-entropy oxides(HEOs)offer enhanced stability compared to conventional doping modifications,rational element selection for optimizing OR reversibility remains unexplored.Here,we propose an entropy engineering design paradigm for “oxygen-anchoring”,where optimal cation electronegativity(>Mn,1.55)and d(3d/4d)-p orbital hybridization synergistically enhance transition metal–oxygen(TM–O)covalency and stabilize the O2p state.Two high-entropy Li-rich layered oxides:Li_(1.2)Mn_(0.47)Ni_(0.115)Co_(0.115)Mg_(0.02)Ti_(0.02)Al_(0.02)Nb_(0.02)Mo_(0.02)O_(2)(MTANM)and Li_(1.2)Mn_(0.47)Ni_(0.115)Co_(0.115)Mg_(0.02)Ti_(0.02)Cu_(0.02)Nb_(0.02)Mo_(0.02)O_(2)(MTCNM)were synthesized using partial nano-scale precursors and comparatively evaluated.MTCNM exhibits enhanced electrochemical performance and superior oxygen stability compared to MTANM by replacing Al with higher-electronegativity Cu,which possesses improved orbital overlap with oxygen.Both experiments and density functional theory(DFT)calculations demonstrate that element selection changes the covalency of TM–O through altered electronegativity and d orbitals-p orbitals(d-p)hybridization.Further stepwise screening selected the optimal elemental combination Li_(1.2)Mn_(0.47)Ni_(0.115)Co_(0.115)Cr_(0.02)Cu_(0.02)Nb_(0.02)Mo_(0.02)Ru_(0.02)O_(2)(CCNMR),which achieved near 100%capacity retention after 150 cycles at 1 C,50℃,with its voltage decay effectively suppressed.This work establishes a rational element-screening paradigm for entropy-stabilized OR chemistry in high-energy cathodes.
基金supported by the National Key Scientific Research Project(No.2022YFB2502300)the National Natural Science Foundation of China(No.52071085).
文摘P3-type manganese-iron-based cathodes with high specific capacity and abundant resource have attracted considerable attention for sodium-ion batteries.However,the long-term cycle stability of P3-type cathodes is still not satisfactory.In this work,we design a new quaternary manganese-iron-based cathode material(P3-Na_(0.54)Mn_(0.64)Fe_(_(0.1)6)Mg_(0.1)Cu_(0.1)O_(2))by Cu substitution.The strong covalent Cu-O bonds improve the structural stability and the reversibility of O redox during charge and discharge processes.Cu substitution also mitigates the structure change with less unit cell volume variation,and improves the Na-ion transport kinetics effectively.As a result,NMFMC delivers much improved cycling stability and rate capability compared with NMFM.It reveals that the charge compensation of NMFMC is mainly contributed by Mn^(3+/4+),Fe^(3+/3.5+)and O_(2-/-)during the charge and discharge processes,and Cu substitution can also enhance the activity and reversibility of Fe redox.This strategy provides a new pathway toward improving the stability and O redox reversibility of P3-type cathode materials for sodium-ion batteries.
文摘为分析集成三维点云逆向建模方法(integrated 3D point cloud reverse modeling,IPCRM)在建立薄厚型钢构件三维模型时的精度表现,以局部变形角钢为研究对象,利用SfM(structure from motion)-MVS(multi-view stereo)算法建立其三维点云模型,借助逆向建模技术生成曲面模型,重点开展了模型精度验证试验.结果表明:各表面形状特征参数的相对误差均在8%以内(吻合度验证);4种角钢模型与实际角钢间无显著性差异(P值,P=0.99),且角钢厚度对模型精度无显著性影响(P值,P=0.95),结论在95%的置信度水平下成立(差异显著性验证).研究结果为后续算法优化及利用此类方法进行合理的钢构件局部变形损伤检测与承载性能评价提供依据.
