碳包覆多孔Fe_(3)O_(4)锂离子电池负极材料

Carbon coating porous Fe_(3)O_(4) anode materials for lithium-ion batteries

本文采用后期易处理的葡萄糖和尿素为混合造孔剂,通过简单的水热以及煅烧法获到多孔前驱体Fe_(3)O_(4),并通过碳热还原的方法获得了碳包覆核壳结构CP-Fe_(3)O_(4)@C。以多孔Fe_(3)O_(4)为核心,在其外围包裹均匀的碳层能够有效抑制Fe_(3)O_(4)在循环过程中的体积形变,抑制活性材料的膨胀破碎,提高活性材料的电化学性能。将CP-Fe_(3)O_(4)@C组装成扣式电池,通过充放电结果显示,CP-Fe_(3)O_(4)@C在0.3 A·g^(-1)的电流密度下循环200圈后的比容量为785 mAh·g^(-1)。通过CP-Fe_(3)O_(4)@C倍率性能的反应动力学计算,当循环伏安的扫描速率为5 mV·s^(-1)时,赝电容占总容量的比例为87%。

This article uses glucose and urea,which are easy to handle in the later stage,as the mixed pore former,to synthesize the porous precursor Fe_(3)O_(4)through simple hydrothermal and calcination methods.Subsequently,the carbon-doped core-shell structure CP-Fe_(3)O_(4)@C was obtained by carbothermal reduction method.With porous Fe_(3)O_(4)as the core,a uniform carbon layer wrapped around,which can effectively inhibit the volume deformation of Fe_(3)O_(4)during the cycle,inhibit the expansion and fragmentation of the active material,and improve the electrochemical performance of the active material.The charge and discharge results showed that the specific capacity of CP-Fe_(3)O_(4)@C after 200 cycles at a current density of 0.3 A·g^(-1)was 785 mAh·g^(-1)when the CP-Fe_(3)O_(4)@C was assembled into a button cell.According to the calculation of the reaction kinetics of CP-Fe_(3)O_(4)@C rate performance,the proportion of pseudo-capacitance to the total capacity was 87%when the scan rate of cyclic voltammetry is 5 mV·s^(-1).