Doping have been considered as a prominent strategy to stabilize crystal structure of battery materials during the insertion and removal of alkali ions.The instructive knowledge and experience acquired from doping str...Doping have been considered as a prominent strategy to stabilize crystal structure of battery materials during the insertion and removal of alkali ions.The instructive knowledge and experience acquired from doping strategies predominate in cathode materials,but doping principle in anodes remains unclear.Here,we demonstrate that trace element doping enables stable conversion-reaction and ensures structural integrity for potassium ion battery(PIB) anodes.With a synergistic combination of X-ray tomography,structural probes,and charge reconfiguration,we encode the physical origins and structural evolution of electro-chemo-mechanical degradation in PIB anodes.By the multiple ion transport pathways created by the orderly hierarchical pores from "surface to bulk" and the homogeneous charge distribution governed in doped nanodomains,the anisotropic expansion can be significantly relieved with trace isoelectronic element doping into the host lattice,maintaining particle mechanical integrity.Our work presents a close relationship between doping chemistry and mechanical reliability,projecting a new pathway to reengineering electrode materials for next-generation energy storage.展开更多
Migration of transition metal(TM)ions out of the TM layer is detrimental and unavoidable in lithium-rich layered oxides,which drives in-plane cation migration,O_(2)release and energy loss.Since out-of-plane migration ...Migration of transition metal(TM)ions out of the TM layer is detrimental and unavoidable in lithium-rich layered oxides,which drives in-plane cation migration,O_(2)release and energy loss.Since out-of-plane migration generally occurs through tetrahedral interstices(TLi)in the Li layer,doping TLi sites has been believed as a promising way to block migration pathways at the dopant site.However,with only trace dopants(<1at.%)sparsely distributed in bulk,the ability of isolated dopants to suppress cation disorder in undoped regions remains unknown—largely due to no suitable model materials.Here,combining atomic-scale imaging,X-ray diffraction measurements and first-principles calculations,we demonstrate that W6+ions(0.75at.%)can occupy TLi sites in Li_(1.2)Mn_(0.6)Ni_(0.2)O_(2).TLi-site doping maximizes dopant efficiency,as each single W^(6+)ion exerts a long-range Coulomb repulsion on TM/Li^(+)ions in the TM layer,suppressing both in-plane and out-of-plane cation migration over a broad range(∼2nm diameter),in contrast to local stabilization via other doping techniques.Remarkably,cation ordering is preserved for over 250 cycles,far exceeding the limited structural stability(∼50 cycles)typically achieved with conventional modification strategies.Consequently,O2 release and formation of low-voltage Mn^(3+)/Mn^(4+)redox couple are inhibited,resulting in negligible voltage decay.展开更多
Organic semiconductors(OSCs)are showing great promise in large-area wearable devices,optoelectronic displays,logic circuits,and next-generation optoelectronic applications[1-9].Examples include organic field-effect tr...Organic semiconductors(OSCs)are showing great promise in large-area wearable devices,optoelectronic displays,logic circuits,and next-generation optoelectronic applications[1-9].Examples include organic field-effect transistors(OFETs),organic light-emitting diodes(OLEDs),organic photovoltaic cells(OPVs),and sensing devices.However,OSCs encounter significant challenges in widespread commercialization[10-13].Compared with their inorganic counterparts connected by strong covalent bonds,the structural characteristics of OSCs films are predominantly governed by van der Waals interactions[14-19],rendering their optoelectronic properties typically dependent on the synergistic effects between intrinsic properties and extrinsic effects,such as impurities and defects[20-26].展开更多
Nickel-rich layered oxides LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)(x≥0.8)have been recognized as the preferred cathode materials to develop lithium-ion batteries with high energy density(>300 Wh kg^(−1)).However,the poor cy...Nickel-rich layered oxides LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)(x≥0.8)have been recognized as the preferred cathode materials to develop lithium-ion batteries with high energy density(>300 Wh kg^(−1)).However,the poor cycling stability and rate capability stemming from intergranular cracks and sluggish kinetics hinder their commercialization.To address such issues,a multi-scale boron penetration strategy is designed and applied on the polycrystalline LiNi_(0.83)Co_(0.11)Mn_(0.06)O_(2)particles that are pre-treated with pore construction.The lithium-ion conductive lithium borate in grain gaps functions as the grain binder that can bear the strain/stress from anisotropic contraction/expansion,and provides more pathways for lithium-ion diffusion.As a result,the intergranular cracks are ameliorated and the lithium-ion diffusion kinetics is improved.Moreover,the coating layer separates the sensitive cathode surface and electrolyte,helping to suppress the parasitic reactions and related gas evolution.In addition,the enhanced structural stability is acquired by strong B-O bonds with trace boron doping.As a result,the boron-modified sample with an optimized boron content of 0.5%(B5-NCM)exhibits a higher initial discharge capacity of 205.5 mAh g^(−1)at 0.1C(1C=200 mA g^(−1))and improved capacity retention of 81.7%after 100 cycles at 1C.Furthermore,the rate performance is distinctly enhanced by high lithium-ion conductive LBO(175.6 mAh g^(−1)for B5-NCM and 154.6 mAh g^(−1)for B0-NCM at 5C)展开更多
基金supported by the start-up fund and‘‘Young Scientist Studio”of Harbin Institute of Technology(HIT)the National Natural Science Foundation of China(No.U1932205)+1 种基金the Natural Science Funds of Heilongjiang Province(No.ZD2019B001)the HIT Research Institute(Zhao Yuan)of New Materials and the Intelligent Equipment Technology Co.,Ltd.Scientific and Technological Cooperation and Development Fund(No.2017KJHZ002)。
文摘Doping have been considered as a prominent strategy to stabilize crystal structure of battery materials during the insertion and removal of alkali ions.The instructive knowledge and experience acquired from doping strategies predominate in cathode materials,but doping principle in anodes remains unclear.Here,we demonstrate that trace element doping enables stable conversion-reaction and ensures structural integrity for potassium ion battery(PIB) anodes.With a synergistic combination of X-ray tomography,structural probes,and charge reconfiguration,we encode the physical origins and structural evolution of electro-chemo-mechanical degradation in PIB anodes.By the multiple ion transport pathways created by the orderly hierarchical pores from "surface to bulk" and the homogeneous charge distribution governed in doped nanodomains,the anisotropic expansion can be significantly relieved with trace isoelectronic element doping into the host lattice,maintaining particle mechanical integrity.Our work presents a close relationship between doping chemistry and mechanical reliability,projecting a new pathway to reengineering electrode materials for next-generation energy storage.
基金supported by the National Natural Science Foundation of China(22393902,22121005,92372001 and 22393900).This research used resources of the Analysis Platform of New Matter Structure at Nankai University.
文摘Migration of transition metal(TM)ions out of the TM layer is detrimental and unavoidable in lithium-rich layered oxides,which drives in-plane cation migration,O_(2)release and energy loss.Since out-of-plane migration generally occurs through tetrahedral interstices(TLi)in the Li layer,doping TLi sites has been believed as a promising way to block migration pathways at the dopant site.However,with only trace dopants(<1at.%)sparsely distributed in bulk,the ability of isolated dopants to suppress cation disorder in undoped regions remains unknown—largely due to no suitable model materials.Here,combining atomic-scale imaging,X-ray diffraction measurements and first-principles calculations,we demonstrate that W6+ions(0.75at.%)can occupy TLi sites in Li_(1.2)Mn_(0.6)Ni_(0.2)O_(2).TLi-site doping maximizes dopant efficiency,as each single W^(6+)ion exerts a long-range Coulomb repulsion on TM/Li^(+)ions in the TM layer,suppressing both in-plane and out-of-plane cation migration over a broad range(∼2nm diameter),in contrast to local stabilization via other doping techniques.Remarkably,cation ordering is preserved for over 250 cycles,far exceeding the limited structural stability(∼50 cycles)typically achieved with conventional modification strategies.Consequently,O2 release and formation of low-voltage Mn^(3+)/Mn^(4+)redox couple are inhibited,resulting in negligible voltage decay.
基金supported by the National Key Research and Development Program of China(2024YFA1209600 to Li L)the National Natural Science Foundation of China(52225304 and 52073210 to Li L,52403243 to Huang Y)。
文摘Organic semiconductors(OSCs)are showing great promise in large-area wearable devices,optoelectronic displays,logic circuits,and next-generation optoelectronic applications[1-9].Examples include organic field-effect transistors(OFETs),organic light-emitting diodes(OLEDs),organic photovoltaic cells(OPVs),and sensing devices.However,OSCs encounter significant challenges in widespread commercialization[10-13].Compared with their inorganic counterparts connected by strong covalent bonds,the structural characteristics of OSCs films are predominantly governed by van der Waals interactions[14-19],rendering their optoelectronic properties typically dependent on the synergistic effects between intrinsic properties and extrinsic effects,such as impurities and defects[20-26].
基金This work was supported by the National Natural Science Foundation of China(51874360,52122407,and 52174285)the Natural Science Foundation for Distinguished Young Scholars of Hunan Province(2020JJ2047)+1 种基金Key Research and Development Project of Ningxia Hui Autonomous Region(2020BCE01006)the Innovation-Driven Project of Central South University(2020CX027)。
文摘Nickel-rich layered oxides LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)(x≥0.8)have been recognized as the preferred cathode materials to develop lithium-ion batteries with high energy density(>300 Wh kg^(−1)).However,the poor cycling stability and rate capability stemming from intergranular cracks and sluggish kinetics hinder their commercialization.To address such issues,a multi-scale boron penetration strategy is designed and applied on the polycrystalline LiNi_(0.83)Co_(0.11)Mn_(0.06)O_(2)particles that are pre-treated with pore construction.The lithium-ion conductive lithium borate in grain gaps functions as the grain binder that can bear the strain/stress from anisotropic contraction/expansion,and provides more pathways for lithium-ion diffusion.As a result,the intergranular cracks are ameliorated and the lithium-ion diffusion kinetics is improved.Moreover,the coating layer separates the sensitive cathode surface and electrolyte,helping to suppress the parasitic reactions and related gas evolution.In addition,the enhanced structural stability is acquired by strong B-O bonds with trace boron doping.As a result,the boron-modified sample with an optimized boron content of 0.5%(B5-NCM)exhibits a higher initial discharge capacity of 205.5 mAh g^(−1)at 0.1C(1C=200 mA g^(−1))and improved capacity retention of 81.7%after 100 cycles at 1C.Furthermore,the rate performance is distinctly enhanced by high lithium-ion conductive LBO(175.6 mAh g^(−1)for B5-NCM and 154.6 mAh g^(−1)for B0-NCM at 5C)
