Carbon was coated on the surface of LiMnSiOto improve the electrochemical performance as cathode materials, which were synthesized by the solution method followed by heat treatment at 700 ℃ and the solid-state method...Carbon was coated on the surface of LiMnSiOto improve the electrochemical performance as cathode materials, which were synthesized by the solution method followed by heat treatment at 700 ℃ and the solid-state method followed by heat treatment at 950 ℃. It is shown that the cycling performance is greatly enhanced by carbon coating, compared with the pristine LiMnSiOcathode obtained by the solution method. The initial discharge capacity of LiMnSiO/C nanocomposite is 280.9 m Ah/g at 0.05 C with the carbon content of 33.3 wt%. The reasons for the improved electrochemical performance are smaller grain size and higher electronic conductivity due to the carbon coating. The LiMnSiO/C cathode material obtained by the solid-state method exhibits poor cycling performance, the initial discharge capacity is less than 25 m Ah/g.展开更多
In this paper,the authors used the Mixed Coordination EXAFS Analysis Method recently published and IR to study the mixed coordination of Ge in glasses of Li_2O-ZnO-GeO_2 system,a new kind of syperionic conductor.The r...In this paper,the authors used the Mixed Coordination EXAFS Analysis Method recently published and IR to study the mixed coordination of Ge in glasses of Li_2O-ZnO-GeO_2 system,a new kind of syperionic conductor.The results show that when the content of ZnO is fixed,the ratio of [GeO_6] units is increased with the addition of Li_2O until the content of Li_2O is about 15%,and then decreased.The relationship between the ratio of [GeO_6]and the content of Li_2O is consistent with those between n,d of glass and Li_2O content, Therefore the germanium abnormalty can be explained as the change of coordination number.展开更多
Despite their high theoretical capacity and energy density,lithiumsulfur(Li–S)batteries still face challenges such as soluble lithium polysulfides(LiPSs)shuttling and sluggish redox kinetics.In this work,we used a no...Despite their high theoretical capacity and energy density,lithiumsulfur(Li–S)batteries still face challenges such as soluble lithium polysulfides(LiPSs)shuttling and sluggish redox kinetics.In this work,we used a novel MoS_(2)-Mo_(2)C heterostructure anchored on a carbon sponge(CS)as a Li_(2)S host to solve these problems.A simple hydrothermal process following carbothermal reduction was used to construct the MoS_(2)-Mo_(2)C heterostructure,enabling control of the phases and integration of MoS_(2) and Mo_(2)C.Structural characterization confirmed the coherent interface of the heterostructure with a precise orientation relationship between the two phases and their uniform distribution.An evaluation of the adsorption and catalytic performance of the material showed that it has an exceptional LiPSs adsorption capacity with faster conversion from Li_(2)S_(4) to Li_(2)S_(2).Density functional theory calculations further confirmed these results.As a result,the cathode had a high initial discharge capacity of 693 mAh g^(−1) at 0.2 C and achieved stable cycling at 2 C for 500 cycles with a low decay rate of 0.107%per cycle.The heterostructure design,coupled with the macroporous CS framework,effectively prevented the shuttling and increased sulfur utilization,offering a promising way to produce practical high-energydensity Li–S batteries.展开更多
Co_(3)S_(4)electrocatalysts with mixed valences of Co ions and excellent structural stability possess favorable oxygen evolution reaction(OER)activity,yet challenges remain in fabricating rechargeable lithiumoxygen ba...Co_(3)S_(4)electrocatalysts with mixed valences of Co ions and excellent structural stability possess favorable oxygen evolution reaction(OER)activity,yet challenges remain in fabricating rechargeable lithiumoxygen batteries(LOBs)due to their poor OER performance,resulting from poor electrical conductivity and overly strong intermediate adsorption.In this work,fancy double heterojunctions on 1T/2H-MoS_(2)@Co_(3)S_(4)(1T/2H-MCS)were constructed derived from the charge donation from Co to Mo ions,thus inducing the phase transformation of Mo S_(2)from 2H to 1T.The unique features of these double heterojunctions endow the1T/2H-MCS with complementary catalysis during charging and discharging processes.It is worth noting that 1T-Mo S2@Co3S4could provide fast Co-S-Mo electron transport channels to promote ORR/OER kinetics,and 2H-MoS_(2)@Co_(3)S_(4)contributed to enabling moderate egorbital occupancy when adsorbed with oxygen-containing intermediates.On the basis,the Li_(2)O_(2)nucleation route was changed to solution and surface dual pathways,improving reversible deposition and decomposition kinetics.As a result,1T/2H-MCS cathodes exhibit an improved electrocatalytic performance compared with those of Co_(3)S_(4)and Mo S2cathodes.This innovative heterostructure design provides a reliable strategy to construct efficient transition metal sulfide catalysts by improving electrical conductivity and modulating adsorption toward oxygenated intermediates for LOBs.展开更多
The electrolyte additive,lithium nitrate(LiNO_(3)),is widely recognized for suppressing dendritic lithium growth in anode-free lithium metal batteries,yet its stabilizing effect is transient,and the mechanistic origin...The electrolyte additive,lithium nitrate(LiNO_(3)),is widely recognized for suppressing dendritic lithium growth in anode-free lithium metal batteries,yet its stabilizing effect is transient,and the mechanistic origin of this limitation has remained unresolved.Here,we uncover the origin of this behavior through a comprehensive analysis driven by artifact/damage-free direct cryogenic transmission electron microscopy,which enabled one of the most chemically specific and morphologically intuitive visualizations to date of intact solid-electrolyte interphases(SEIs)and lithium growth.Contrary to conventional interpretations centered on nitrogen-rich or single-component SEIs,we reveal that LiNO_(3) rapidly generates lithium hydroxide(LiOH)and lithium oxide(Li_(2)O)rich interphases,whose complementary functions—ionic transport through LiOH and mechanical robustness from Li_(2)O—synergistically suppress whisker nucleation and favor compact,particle-like growth.Over the extended plating,however,depletion of these species in combination with crystallographically favored orientations drives the particle-towhisker transition,explaining why the effectiveness of LiNO_(3) is inherently limited.This direct mechanistic visualization resolves a long-standing ambiguity regarding the transient efficacy of LiNO_(3) and reframes its function from a nitrogen-driven mechanism to a synergistic dual oxygen-interphase framework.Beyond mechanistic clarification,these findings establish that continuous regeneration of LiOH and Li_(2)O is essential for stable lithium deposition,offering a design principle for the development of durable electrolytes in high-performance anode-free lithium metal batteries.展开更多
基金Funded by the National Natural Science Foundation of China(No.51372136)Shenzhen Basic Research Project(No.CYJ20130402145002372)
文摘Carbon was coated on the surface of LiMnSiOto improve the electrochemical performance as cathode materials, which were synthesized by the solution method followed by heat treatment at 700 ℃ and the solid-state method followed by heat treatment at 950 ℃. It is shown that the cycling performance is greatly enhanced by carbon coating, compared with the pristine LiMnSiOcathode obtained by the solution method. The initial discharge capacity of LiMnSiO/C nanocomposite is 280.9 m Ah/g at 0.05 C with the carbon content of 33.3 wt%. The reasons for the improved electrochemical performance are smaller grain size and higher electronic conductivity due to the carbon coating. The LiMnSiO/C cathode material obtained by the solid-state method exhibits poor cycling performance, the initial discharge capacity is less than 25 m Ah/g.
文摘In this paper,the authors used the Mixed Coordination EXAFS Analysis Method recently published and IR to study the mixed coordination of Ge in glasses of Li_2O-ZnO-GeO_2 system,a new kind of syperionic conductor.The results show that when the content of ZnO is fixed,the ratio of [GeO_6] units is increased with the addition of Li_2O until the content of Li_2O is about 15%,and then decreased.The relationship between the ratio of [GeO_6]and the content of Li_2O is consistent with those between n,d of glass and Li_2O content, Therefore the germanium abnormalty can be explained as the change of coordination number.
文摘Despite their high theoretical capacity and energy density,lithiumsulfur(Li–S)batteries still face challenges such as soluble lithium polysulfides(LiPSs)shuttling and sluggish redox kinetics.In this work,we used a novel MoS_(2)-Mo_(2)C heterostructure anchored on a carbon sponge(CS)as a Li_(2)S host to solve these problems.A simple hydrothermal process following carbothermal reduction was used to construct the MoS_(2)-Mo_(2)C heterostructure,enabling control of the phases and integration of MoS_(2) and Mo_(2)C.Structural characterization confirmed the coherent interface of the heterostructure with a precise orientation relationship between the two phases and their uniform distribution.An evaluation of the adsorption and catalytic performance of the material showed that it has an exceptional LiPSs adsorption capacity with faster conversion from Li_(2)S_(4) to Li_(2)S_(2).Density functional theory calculations further confirmed these results.As a result,the cathode had a high initial discharge capacity of 693 mAh g^(−1) at 0.2 C and achieved stable cycling at 2 C for 500 cycles with a low decay rate of 0.107%per cycle.The heterostructure design,coupled with the macroporous CS framework,effectively prevented the shuttling and increased sulfur utilization,offering a promising way to produce practical high-energydensity Li–S batteries.
基金financially supported by the National Natural Science Foundation of China(U21A20311,U24A2040,52171141,52272117)the Natural Science Foundation of Shandong Province(ZR2022JQ19)+3 种基金the Key Technology Research Project of Shandong Province(2023CXGC010202)the Taishan Industrial Experts Program(TSCX202306142)the Core Facility Sharing Platform of Shandong Universitythe Foundation of Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education),Nankai University。
文摘Co_(3)S_(4)electrocatalysts with mixed valences of Co ions and excellent structural stability possess favorable oxygen evolution reaction(OER)activity,yet challenges remain in fabricating rechargeable lithiumoxygen batteries(LOBs)due to their poor OER performance,resulting from poor electrical conductivity and overly strong intermediate adsorption.In this work,fancy double heterojunctions on 1T/2H-MoS_(2)@Co_(3)S_(4)(1T/2H-MCS)were constructed derived from the charge donation from Co to Mo ions,thus inducing the phase transformation of Mo S_(2)from 2H to 1T.The unique features of these double heterojunctions endow the1T/2H-MCS with complementary catalysis during charging and discharging processes.It is worth noting that 1T-Mo S2@Co3S4could provide fast Co-S-Mo electron transport channels to promote ORR/OER kinetics,and 2H-MoS_(2)@Co_(3)S_(4)contributed to enabling moderate egorbital occupancy when adsorbed with oxygen-containing intermediates.On the basis,the Li_(2)O_(2)nucleation route was changed to solution and surface dual pathways,improving reversible deposition and decomposition kinetics.As a result,1T/2H-MCS cathodes exhibit an improved electrocatalytic performance compared with those of Co_(3)S_(4)and Mo S2cathodes.This innovative heterostructure design provides a reliable strategy to construct efficient transition metal sulfide catalysts by improving electrical conductivity and modulating adsorption toward oxygenated intermediates for LOBs.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.RS-2024-00406724(50%)RS-2023-00222411,RS-2025-24533073)+2 种基金the Korea Basic Science Institute(National research Facilities and Equipment Center)grant funded by the Korea government(MOE)(RS-2024-00436346)the Korea Institute for Advancement of Technology(KIAT)grant funded by the Korea government(MOTIE)(RS-2024-00417730,HRD Program for Industrial Innovation)the research fund of Hanyang University(HY-202100000003295)。
文摘The electrolyte additive,lithium nitrate(LiNO_(3)),is widely recognized for suppressing dendritic lithium growth in anode-free lithium metal batteries,yet its stabilizing effect is transient,and the mechanistic origin of this limitation has remained unresolved.Here,we uncover the origin of this behavior through a comprehensive analysis driven by artifact/damage-free direct cryogenic transmission electron microscopy,which enabled one of the most chemically specific and morphologically intuitive visualizations to date of intact solid-electrolyte interphases(SEIs)and lithium growth.Contrary to conventional interpretations centered on nitrogen-rich or single-component SEIs,we reveal that LiNO_(3) rapidly generates lithium hydroxide(LiOH)and lithium oxide(Li_(2)O)rich interphases,whose complementary functions—ionic transport through LiOH and mechanical robustness from Li_(2)O—synergistically suppress whisker nucleation and favor compact,particle-like growth.Over the extended plating,however,depletion of these species in combination with crystallographically favored orientations drives the particle-towhisker transition,explaining why the effectiveness of LiNO_(3) is inherently limited.This direct mechanistic visualization resolves a long-standing ambiguity regarding the transient efficacy of LiNO_(3) and reframes its function from a nitrogen-driven mechanism to a synergistic dual oxygen-interphase framework.Beyond mechanistic clarification,these findings establish that continuous regeneration of LiOH and Li_(2)O is essential for stable lithium deposition,offering a design principle for the development of durable electrolytes in high-performance anode-free lithium metal batteries.
