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In-situ construction of conducting alloy interphase towards modulating Li-ion storage kinetics
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作者 Lingjie Li Dandan Wang +5 位作者 Xiaoxia Xu Xiaosong Guo Jing Liu changming mao Zhonghua Zhang Guicun Li 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2021年第5期395-403,共9页
Interface engineering strategy shows great promise in promoting the reaction kinetic and cycling performance in the field of electrochemical energy storage application.In this work,an in-situ interface growth strategy... Interface engineering strategy shows great promise in promoting the reaction kinetic and cycling performance in the field of electrochemical energy storage application.In this work,an in-situ interface growth strategy is proposed to introduce a robust and conducting MoGe_(2) alloy interphase between the electrochemical active Ge nanoparticle and flexible MoS_(2) nanosheets to modulate their Li-ion storage kinetics.The structural evolution processes of the Ge@MoGe_(2)@MoS_(2) composite are unraveled,during which the initially-generated Ge metals serve as a crucial reduction mediator in the formation of MoGe_(2) species bridging the Ge and MoS_(2).The as-generated MoGe_(2) interface,chemically bonding with both Ge and MoS_(2),possesses multi-fold merits,including the maintaining stable framework of electrochemically inactive Mo matrix to buffer the strain-stress effect and the"welding spot"effects to facilitate the efficient Li^(+)/e^(-)conduction.As well,the introduction of MoGe_(2) interface leads to a unique sequential lithiation/de^(-)lithiation process,namely in the order of the electrochemically active MoS_(2)-MoGe_(2)-Ge during lithiation and vice versa,during which the electrode strain could be more effectively released.Benefited from the robust and rigid MoGe_(2) interface,the delicately designed Ge@MoGe_(2)@MoS_(2) composite exhibits an improved charge/discharge performances(866.7 mAh g^(-1) at 5.0 A g^(-1) and 838.5 mAh g^(-1) after 400 cycles)while showing a high tap density of 1.23 g cm^(-3).The as-proposed in-situ interface growth strategy paves a new avenue for designing novel high-performance electrochemical energy storage materials. 展开更多
关键词 Lithium-ion batteries Interface MoGe_(2) ANODE Inhibit volume expansion
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Terminal sulfur atoms formation via defect engineering strategy to promote the conversion of lithium polysulfides 被引量:2
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作者 Yuanchang Li Wenda Li +6 位作者 Xiujuan Yan Zhenfang Zhou Xiaosong Guo Jing Liu changming mao Zhonghua Zhang Guicun Li 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2022年第8期221-231,共11页
The defect engineering shows great potential in boosting the conversion of lithium polysulfides intermediates for high energy density lithium-sulfur batteries(LSBs),yet the catalytic mechanisms remain unclear.Herein,t... The defect engineering shows great potential in boosting the conversion of lithium polysulfides intermediates for high energy density lithium-sulfur batteries(LSBs),yet the catalytic mechanisms remain unclear.Herein,the oxygen-defective Li_(4)Ti_(5)O_(12)-xhollow microspheres uniformly encapsulated by N-doped carbon layer(OD-LTO@NC)is delicately designed as an intrinsically polar inorganic sulfur host for the research on the catalytic mechanism.Theoretical simulations have demonstrated that the existence of oxygen deficiencies enhances the adsorption capability of spinel Li_(4)Ti_(5)O_(12)towards soluble lithium polysulfides.Some-S-S-bonds of the Li2S6on the defective Li_(4)Ti_(5)O_(12)surface are fractured by the strong adsorption force,which allows the inert bridging sulfur atoms to be converted into the susceptible terminal sulfur atoms,and reduces the activation energy of the polysulfide conversion in some degree.In addition,with the N-doped carbon layer,secondary hollow microspheres architecture built with primary ultrathin nanosheets provide a large amount of void space and active sites for sulfur storage,adsorption and conversion.The as-designed sulfur host exhibits a remarkable rate capability of 547 m Ah g^(-1)at 4C(1 C=1675 m A g^(-1))and an outstanding long-term cyclability(519 m Ah g^(-1)after 1000 cycles at 3 C).Besides,a high specific capacity of 832 m Ah g^(-1)is delivered even after 100 cycles under a high sulfur mass loading of 3.2 mg cm^(-2),indicating its superior electrochemical performances.This work not only provides a strong proof for the application of oxygen defect in the adsorption and catalytic conversion of lithium polysulfides,but offers a promising avenue to achieve high performance LSBs with the material design concept of incorporating oxygen-deficient spinel structure with hierarchical hollow frameworks. 展开更多
关键词 Lithium-sulfur batteries Oxygen deficiency Lithium titanate Hierarchical hollow microsphere Conversion kinetics
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Selenium vacancies enable efficient immobilization and bidirectional conversion acceleration of lithium polysulfides for advanced Li-S batteries 被引量:1
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作者 Yuanchang Li Zhenfang Zhou +6 位作者 Yong Li Zhonghua Zhang Xiaosong Guo Jing Liu changming mao Zhenjiang Li Guicun Li 《Nano Research》 SCIE EI CSCD 2022年第8期7234-7246,共13页
Heterostructures composed of oxides and sulfides(nitrides or carbides)show great potential as sulfur host additives because of the strong adoptability of oxides and catalytic capability of sulfides towards the notorio... Heterostructures composed of oxides and sulfides(nitrides or carbides)show great potential as sulfur host additives because of the strong adoptability of oxides and catalytic capability of sulfides towards the notorious lithium polysulfides(LiPSs).However,the migration and conversion pathway of LiPSs is seriously confined at a localized interface with inadequate active sites.In this work,the introduction of selenium vacancies into VSe_(2−x)has been demonstrated to successfully synergize the adsorbability and catalytic reactions of LiPSs at an integrated functional surface.The N-doped carbon nanosheets-assembled flower architectures embedded with selenium vacancy-rich VSe_(2−x)and partial vanadium oxides have been controllably synthesized and employed as the cathode additives for lithium-sulfur(Li-S)batteries.Both the experiments and first-principle calculations reveal their strong adsorption to LiPSs and their bidirectional catalytic functionality towards the conversion between S8 and Li_(2)S.As expected,the charge and discharge kinetics of VSe_(2−x)containing sulfur cathodes is fundamentally improved(an outstanding rate capabilitiy with 693.7 mAh·g^(−1)at 2 C,a remarkable long-term cyclability within 1,000 cycles at 2 C with S loading 2.27 mg·cm^(−2),and an excellent areal capacity with 3.44 mAh·cm^(−2)within 100 cycles at 0.5 C).This work presents an effective resolution to couple the adsorbability and catalytic reactions of LiPSs at the material design perspective,and the insights on bidirectional catalytic functionality are of vital to develop functional materials for advanced Li-S batteries. 展开更多
关键词 lithium-sulfur batteries selenium vacancies vanadium selenide bidirectional catalysis conversion kinetics
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