双功能氮氧化钛-碳涂层提升高容量锂离子电池用SiO_(x)的储锂性能

Boosting lithium storage of SiO_(x) via a dual-functional titanium oxynitride-carbon coating for robust and high-capacity lithium-ion batteries

非化学计量微米氧化硅(SiO_(x))由于其高理论容量和低成本,有望成为锂离子电池石墨负极材料的替代品.然而,SiO_(x)的实际应用仍然受到其较差的固有导电性和循环过程中明显的体积变化的阻碍.在本工作中,为了同时解决这些问题,我们使用可规模化的溶剂热和热还原方法制备了具有TiO_(1-y)Ny-C涂层的SiO_(x)基负极材料(SiO_(x)@TiON-C).我们通过系统性研究发现,TiO_(1-y)Ny-C涂层可以适应SiO_(x)循环过程中大的体积变化且有效提高其导电性.因此,SiO_(x)@TiON-C负极具有突出的储锂性能.具体而言,SiO_(x)@TiON-C负极可以在500 mA g^(-1)的电流密度下循环500圈后仍保持750.2 mA h g^(-1)的优异可逆容量,75.1%的初始库仑效率和优异的倍率性能.这项工作为促进下一代锂离子电池微米SiO_(x)基负极材料的实际商业化提供了一种很有前途的方法.

Nonstoichiometric microstructured silicon suboxide(SiO_(x))could be an attractive alternative to graphite as the anode materials of lithium-ion batteries(LIBs)due to its high theoretical capacity and low cost.However,practical applications of SiO_(x) are hampered by their inferior inherent conductivity and distinct volume changes during cycling.In this work,in order to address these issues simultaneously,we designed and fabricated SiO_(x)-based anode materials with TiO_(1-y)Ny-carbon coating layer(SiO_(x)@TiON-C)using a scal-able solvothermal and thermal reduction method.Our sys-tematic investigations suggest that TiO_(1-y)Ny and the C coating layer could accommodate large volume variation and promote electrical conductivity of SiO_(x) during cycling,respectively.As a result,the as-prepared SiO_(x)@TiON-C anode exhibits su-perior lithium storage performance.Specifically,the resultant SiO_(x)@TiON-C anode could deliver an outstanding reversible capacity of 750.2 mA h g^(-1) at 500 mA g^(-1) after 500 cycles,high initial Coulombic efficiency of 75.1%and excellent rate cap-ability.This work offers a promising approach to promote the practical commercialization of microstructured SiO_(x)-based anode materials for next-generation LIBs.