多孔竹炭负载SnO_(2)的制备及其电化学性能研究

Preparation and Electrochemical Performance of SnO_(2) Supported on Porous Bamboo Charcoal

多孔竹炭为无定形碳,具有丰富的孔结构,孔径分布在1~6 nm之间,且具有较大的孔体积(1.21 cm^(3)/g)。本文以多孔竹炭为载体,采用溶胶-凝胶法制得B_(2)O_(3)-SnO_(2)/C复合材料。SEM和TEM结果显示SnO_(2)和B_(2)O_(3)均匀分布在多孔竹炭表面。多孔竹炭和B_(2)O_(3)有效缓冲SnO_(2)可逆反应的体积变化,提高SnO_(2)的循环稳定性。将B_(2)O_(3)-SnO_(2)/C复合材料作为负极组装成锂离子半电池,进行电化学性能测试,在1 C(1 C=372 mA/g)倍率下充放电循环200次结束后仍然保留649.9 mAh/g的放电比容量,放电比容量保留率为58.6%。B_(2)O_(3)-SnO_(2)/C复合材料充放电过程受扩散和电容两种行为控制,电容控制的贡献率随着扫描速率的增大而增大。

Porous bamboo charcoal is amorphous carbon with abundant pore structure,and the pore size ranges from 1 nm to 6 nm,with a large pore volume(1.21 cm^(3)/g).Using porous bamboo charcoal as the carrier,the B_(2)O_(3)-SnO_(2)/C composite material was prepared by the sol-gel method.SEM and TEM results show that SnO_(2) and B_(2)O_(3) are uniformly distributed on the surface of the porous bamboo charcoal.The porous bamboo charcoal and B_(2)O_(3) effectively accommodate the volume change of the reversible reaction of SnO_(2) and improve the cycling stability of SnO_(2).The lithium-ion batteries were assembled by B_(2)O_(3)-SnO_(2)/C composite materials as anode,and the electrochemical performance was tested.After 200 cycles,the discharge specific capacity still reaches 649.9 mAh/g at 1 C(1 C=372 mA/g)rate,and the discharge specific capacity retention rate is as high as 58.6%.The charge-discharge process of B_(2)O_(3)-SnO_(2)/C porous composites is controlled by diffusion and capacitance behavior,and the contribution rate of capacitance control increases with the increase of scan rate.