非化学计量的氧化硅(SiO_(x),0<x<2)是一种很有前途的锂电池负极材料.然而,它的本征电导率低,体积膨胀明显.特别是,由于连续的电解液消耗,很难形成稳定的固体电解质界面.本工作将空心氧化硅微球包裹在钴碳(Co-C)骨架及其衍生的氮...非化学计量的氧化硅(SiO_(x),0<x<2)是一种很有前途的锂电池负极材料.然而,它的本征电导率低,体积膨胀明显.特别是,由于连续的电解液消耗,很难形成稳定的固体电解质界面.本工作将空心氧化硅微球包裹在钴碳(Co-C)骨架及其衍生的氮掺杂碳纳米管网络(N-CNTs)中.这种设计解决了电解液消耗和SEI层重复形成的问题,并实现了快速动力学.此外,所制备材料的柔性碳纳米管和坚固金属-碳框架提供力学支撑,可以适应SiO_(x)体积变化.h-SiO_(x)@Co@N-CNTs作为锂离子电池负极材料,具有优异的循环稳定性和高倍率性能.以0.2 A g^(-1)的电流密度循环370次,容量为701 mAh g^(-1),容量保持率为100%.另外,在1.0 A g^(-1)电流密度下循环500圈,容量没有衰减.结果表明,所合成的锂离子电池结构具有一定的优越性,对材料的优化也有一定的启发作用.展开更多
Chemical prelithiation is widely proven to be an effective strategy to address the low initial coulombic efficiency(ICE)of promising SiO_(x) anode.Though the reagent composition has been widely explored,the Li^(+) sol...Chemical prelithiation is widely proven to be an effective strategy to address the low initial coulombic efficiency(ICE)of promising SiO_(x) anode.Though the reagent composition has been widely explored,the Li^(+) solvation structure,which practically plays the cornerstone role in the prelithiation ability,rate,uniformility,has rarely been explored.A novel environmentally-friendly reagent with weak solvent cyclopentyl methyl ether(CPME)is proposed that enables both improved ICE and spatial homogeneous solid electrolyte interphase(SEl).And the prelithiation behavior and mechanism were explored focused on the Li^(+) solvation structure.Both theoretical investigation and spectroscopic results suggest that weak solvent feature of CPME reduces the solvent coordination number and decreases the Li^(+) desolvation energy.展开更多
The commercialized binder carboxymethyl cellulose sodium(CMC-Na)is considered unsuitable for micro-sized SiO_(x) anode as it cannot endure the large volume change to retain the conductive network during repeated charg...The commercialized binder carboxymethyl cellulose sodium(CMC-Na)is considered unsuitable for micro-sized SiO_(x) anode as it cannot endure the large volume change to retain the conductive network during repeated charge/discharge cycles.Herein,a small amount of silicon nanoparticles(SiNPs)is added during slurry preparation process as“nano-combs”to unfold the convoluted CMC-Na polymer chains so that they undergo a coilto-stretch transition by interaction between polar groups(e.g.,-OH,-COONa)of polymer and SiNPs’large surface.Through maximizing the utilization of binders,a uniform conductive network is constructed with increased interfacial contact with micro-sized SiO_(x).As a result,the SiO_(x) electrode with optimized(10 wt%)SiNPs addition shows significantly improved initial capacity and cycling performance.Through revisiting CMCNa,a currently deemed unqualified binder in SiO_(x) anode,this work gives a brand-new perspective on the failing mechanism of Si-based anode materials and an improving strategy for electrode preparation.展开更多
基金financially supported by the National Natural Science Foundation of China(51874362,22209208)Key Research and Development Program of Hunan Province(2023GK2015)the Science and Technology Innovation Leader Program of Hunan Province(2022RC3049)。
文摘非化学计量的氧化硅(SiO_(x),0<x<2)是一种很有前途的锂电池负极材料.然而,它的本征电导率低,体积膨胀明显.特别是,由于连续的电解液消耗,很难形成稳定的固体电解质界面.本工作将空心氧化硅微球包裹在钴碳(Co-C)骨架及其衍生的氮掺杂碳纳米管网络(N-CNTs)中.这种设计解决了电解液消耗和SEI层重复形成的问题,并实现了快速动力学.此外,所制备材料的柔性碳纳米管和坚固金属-碳框架提供力学支撑,可以适应SiO_(x)体积变化.h-SiO_(x)@Co@N-CNTs作为锂离子电池负极材料,具有优异的循环稳定性和高倍率性能.以0.2 A g^(-1)的电流密度循环370次,容量为701 mAh g^(-1),容量保持率为100%.另外,在1.0 A g^(-1)电流密度下循环500圈,容量没有衰减.结果表明,所合成的锂离子电池结构具有一定的优越性,对材料的优化也有一定的启发作用.
基金supported by projects from the National Natural Science Foundation of China(No.U20A20145)State Key Laboratory of Polymer Materials Engineering(No.sklpme2020-3-02)+6 种基金Sichuan Provincial Department of Science and Technology(No.2020YFG0022,No.2022YFG0124)Dazhou Department of Science and Technology(No.21ZDYF0001)Guangyuan Department of Science and Technology(No.22ZDYF0047)Sichuan Province Science and Technology Achievement Transfer and Transformation Project(No.21ZHSF0111)2020 Strategic Cooperation Project between Sichuan University and Suining Municipal People's Government Government(No.20221500008704170)the Open Project of State Key Laboratory of Environment-friendly Energy.Materials(No.20KFHG07)Start-up funding of Chemistry and Chemical Engineering Guangdong Laboratory(No.2122010).
文摘Chemical prelithiation is widely proven to be an effective strategy to address the low initial coulombic efficiency(ICE)of promising SiO_(x) anode.Though the reagent composition has been widely explored,the Li^(+) solvation structure,which practically plays the cornerstone role in the prelithiation ability,rate,uniformility,has rarely been explored.A novel environmentally-friendly reagent with weak solvent cyclopentyl methyl ether(CPME)is proposed that enables both improved ICE and spatial homogeneous solid electrolyte interphase(SEl).And the prelithiation behavior and mechanism were explored focused on the Li^(+) solvation structure.Both theoretical investigation and spectroscopic results suggest that weak solvent feature of CPME reduces the solvent coordination number and decreases the Li^(+) desolvation energy.
基金support from the National Key R&D Program of China(2016YFB0700600,2020YFB0704500)China Postdoctoral Science Foundation(2019M660317)+1 种基金Engineering and Physical Sciences Research Council,UK(EP/S000933/1)Shenzhen Science and Technology Program(Grant No.RCBS20200714114820077).
文摘The commercialized binder carboxymethyl cellulose sodium(CMC-Na)is considered unsuitable for micro-sized SiO_(x) anode as it cannot endure the large volume change to retain the conductive network during repeated charge/discharge cycles.Herein,a small amount of silicon nanoparticles(SiNPs)is added during slurry preparation process as“nano-combs”to unfold the convoluted CMC-Na polymer chains so that they undergo a coilto-stretch transition by interaction between polar groups(e.g.,-OH,-COONa)of polymer and SiNPs’large surface.Through maximizing the utilization of binders,a uniform conductive network is constructed with increased interfacial contact with micro-sized SiO_(x).As a result,the SiO_(x) electrode with optimized(10 wt%)SiNPs addition shows significantly improved initial capacity and cycling performance.Through revisiting CMCNa,a currently deemed unqualified binder in SiO_(x) anode,this work gives a brand-new perspective on the failing mechanism of Si-based anode materials and an improving strategy for electrode preparation.
