摘要
以磷酸二氢钠(NaH_(2)PO_(4))为磷源,通过溶剂热法制备了P掺杂的TiO_(2)/C(P-TiO_(2)/C)纳米管以改善TiO_(2)的储锂性能.电化学测试表明:P-TiO_(2)/C负极具有高的比容量(在0.1 A·g^(-1)的电流密度下达到335 mAh·g^(-1))、优异的倍率性能(在2.0 A·g^(-1)的电流密度下为92 mAh·g^(-1))及循环性能(在1.0 A·g^(-1)的电流密度下经过1000次循环后放电比容量仍维持在135 mAh·g^(-1)).并且,P-TiO_(2)/C在2 mV·s^(-1)时的赝电容贡献约为96%.由P-TiO_(2)/C负极和活性炭正极组装的锂离子电容器在250 W·kg^(-1)的功率密度下能量密度能够达到74.7 Wh·kg^(-1).此外,该锂离子电容器在10000次循环后比电容保持率约为43%.此外,该器件在1.0A·g^(-1)下循环10000次后充满电仍可点亮18只红色的LED灯组成的“LIC”字样.该工作为高性能锂离子电容器TiO_(2)负极材料的设计提供了思路.
As an anode material for Li-ion capacitors(LICs),TiO_(2)exhibits pseudocapacitive behavior,low sodium storage potential and small structural changes in lithium storage process.However,poor conductivity and slow ion diffusion lead to sluggish lithium storage kinetics.Using sodium dihydrogen phosphate(NaH_(2)PO_(4))as a phosphorus source,P-doped TiO_(2)/C(P-TiO_(2)/C)nanotubes are prepared by a simple solvothermal method to improve the lithium storage performance of TiO_(2).The P-TiO_(2)/C nanotubes composed of nanosheets grown vertically on the surface can provide effective contact areas between electrolyte and active materials.And the C and P in P-TiO_(2)/C are derived from the carbonization of alcohols and decomposition of NaH2PO4.P-doping easily causes P—O—Ti bond formed in TiO_(2)by P5+replacing part of Ti4+,which can effectively improve the conductivity of TiO_(2).Electrochemical tests show that the P-TiO_(2)/C anode for Li-ion batteries exhibits a high specific capacity(335 mAh·g^(-1)at a current density of 0.1 A·g^(-1)),excellent rate capability(92 mAh·g^(-1)at a current density of2.0 A·g^(-1))and long cycle performance(135 mAh·g^(-1)at a current density of 1.0 A·g^(-1)after 1000 cycles).In addition,the pseudocapacitive contribution of P-TiO_(2)/C anode is about 96%at a scan rate of 2 mV·s^(-1).The superior lithium storage performance of P-TiO_(2)/C nanotubes is derived from the P-doping in TiO_(2),which can change the electron structure of TiO_(2),which facilitates the electrons transport and lithium diffusion kinetics.The LICs assembled by P-TiO_(2)/C anodes and activated carbon cathodes have a high energy density of 74.7 Wh·kg^(-1)at a power density of 250 W·kg^(-1),which are higher than some LICs based on titanic-based compound anodes.And the capacity retention of the LICs is about 43%after 10000 cycles at a current density of 1.0 A·g^(-1).In addition,after 10000 cycles test,a fully charged LICs can still light up the"LIC"model composed of 18 red LED lights.This work provides an idea for the design of TiO_(2)anode materials for high-performance LICs.
作者
张国强
霍京浩
王鑫
郭守武
Zhang,Guoqiang;Huo,Jinghao;Wang,Xin;Guo,Shouwu(School of Materials Science and Engineering,Shaanxi University of Science&Technology,Xi’an 710021;School of Electronic Information and Electrical Engineering,Shanghai Jiao Tong University,Shanghai 200240)
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2023年第1期6-13,共8页
Acta Chimica Sinica
基金
陕西科技大学自然科学基金(No.2016BJ-49)
陕西省自然科学基金(No.2020JM-505)资助
