Post-annealing tailored 3D cross-linked TiNb2O7 nanorod electrode: towards superior lithium storage for flexible lithium-ion capacitors  

退火调控的3D交联TiNb2O7纳米棒电极用于高效柔性锂离子电容器（英文）

作　　者：Bohua Deng Haoyang Dong Tianyu Lei Ning Yue Liang Xiao Jinping Liu 邓伯华;董浩洋;雷田雨;岳宁;肖亮;刘金平(School of Chemistry,Chemical Engineering and Life Sciences,Wuhan University of Technology,Wuhan 430070,China;State Key Laboratory of Advanced Technology for Materials Synthesis and Processing,Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]School of Chemistry,Chemical Engineering and Life Sciences,Wuhan University of Technology,Wuhan 430070,China [2]State Key Laboratory of Advanced Technology for Materials Synthesis and Processing,Wuhan University of Technology,Wuhan 430070,China

出　　处：《Science China Materials》2020年第4期492-504,共13页中国科学（材料科学（英文版）

基　　金：supported by the National Natural Science Foundation of China (51672205, 21673169 and 51972257);the National Key R&D Program of China (2016YFA0202602);the Natural Science Foundation of Hubei Province (2018CFB581)

摘　　要：TiNb2O7 anode materials(TNO)have unique potential for applications in Li-ion capacitors(LICs)due to their high specific capacity of ca.280 mA h g^-1 over a wide anodic Li-insertion potential window.However,their highrate capability is limited by their poor electronic and ionic conductivity.In particular,studies on TNO for LICs are lacking and that for flexible LICs have not yet been reported.Herein,a unique TNO porous electrode with cross-linked nanorods tailored by post-annealing and its application in flexible LICs are reported.This binder-free TNO anode exhibits superior rate performance(~66.3%capacity retention as the rate increases from 1 to 40 C),which is ascribed to the greatly shortened ion-diffusion length in TNO nanorods,facile electrolyte penetration and fast electron transport along the continuous single-crystalline nanorod network.Furthermore,the TNO anode shows an excellent cycling stability up to 2000 cycles and good flexibility(no capacity loss after continuous bending for 500 times).Model flexible LIC assembled with the TNO anode and activated carbon cathode exhibits increased gravimetric and volumetric energy/power densities(~100.6 W h kg^-1/4108.8 W kg^-1;10.7 mW h cm^-3/419.3 mW cm^-3),more superior to previously reported hybrid supercapacitors.The device also efficiently powers an LED light upon 180°bending.TiNb2O7的理论比容量高达280 mA h g^-1,是一类有前景的锂离子电容器负极材料.然而其较差的电子导电性严重限制了其倍率性能的提升.在本文中,我们在柔性碳布表面直接生长3D交联的TiNb2O7纳米棒多孔负极,并将其首次应用于柔性锂离子电容器;碳布的高导电性,单晶纳米棒结构较短的离子/电子传输路径以及良好的结构稳定性,有效提高了材料的倍率性能和循环稳定性.研究表明,Ti Nb2O7负极表现出优异的倍率性能(从1到40 C,容量保持率高达66.3%),出色的循环稳定性(>2000圈),以及良好的柔韧性(连续弯曲500次后容量无损失).此外,将无粘结剂的Ti Nb2O7负极和商用活性炭正极搭配成锂离子电容器,展现出了较高的质量和体积能量/功率密度(~100.6 W h kg^-1/4108.8 W kg^-1;10.7 m W h cm^-3/419.3 mW cm^-3),优于先前报道的混合超级电容器,同时该器件可以在180°弯曲状态下为LED灯供电.

关 键 词：POST-ANNEALING cross-linked nanorods facile electron transport superior rate performance flexible Li-ion capacitors 

分 类 号：TM53[电气工程—电器]