不同形貌碳包覆铌酸钛微球的合成及其储锂性能研究

The Synthesis and Lithium Storage Properties of Carbon Coated TiNb_(2)O_(7)Microspheres with Different Morphologies

因为铌酸钛具有合适的放电电压平台、较长的循环寿命和较高的可逆比容量,所以其被认为是一种理想的锂离子电池负极材料,但因它导电能力差而大大限制了其实际应用.该文通过简易的喷雾干燥法制备了铌酸钛微球,然后将其分别与环糊精、蔗糖和聚乙烯吡咯烷酮混合,在氩气气氛下退火处理制备3种碳包覆的铌酸钛微球.电化学性能测试结果表明:以环糊精为碳源合成的铌酸钛微球展现出最好的倍率性能和循环稳定性,在10.00 C大电流密度下循环1000圈后的可逆比容量保持为134.3 mA·h·g^(-1).

Titanium niobate is considered as an ideal anode material for lithium-ion batteries because of its suitable discharge voltage platform,long cycle life and high reversible specific capacity.However,its practical application is greatly limited by the poor conductivity.In this paper,TiNb_(2)O_(7)microspheres are prepared by a simple spray drying method,and then mixed with cyclodextrin,sucrose and polyvinylpyrrolidone respectively,and annealed in argon atmosphere to prepare three kinds of carbon coated TiNb_(2)O_(7)microspheres.The electrochemical performance test results show that TiNb_(2)O_(7)microspheres synthesized with cyclodextrin as carbon source show the best rate performance and cycle stability.The reversible specific capacity of 134.3 mA·h·g^(-1)is maintained after 1000 cycles at the high current density of 10.00 C.