多孔竹炭负载SnO2的制备及其电化学性能研究

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 cm³/g)。本文以多孔竹炭为载体,采用溶胶-凝胶法制得B₂O₃-SnO₂/C复合材料。SEM和TEM结果显示SnO₂和B₂O₃均匀分布在多孔竹炭表面。多孔竹炭和B₂O₃有效缓冲SnO₂可逆反应的体积变化,提高SnO₂的循环稳定性。将B₂O₃-SnO₂/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%。B₂O₃-SnO₂/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。

Preparation and Electrochemical Performance of SnO2 Supported on Porous Bamboo Charcoal

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 cm³/g). Using porous bamboo charcoal as the carrier, the B₂O₃-SnO₂/C composite material was prepared by the sol-gel method. SEM and TEM results show that SnO₂ and B₂O₃ are uniformly distributed on the surface of the porous bamboo charcoal. The porous bamboo charcoal and B₂O₃ effectively accommodate the volume change of the reversible reaction of SnO₂ and improve the cycling stability of SnO₂. The lithium-ion batteries were assembled by B₂O₃-SnO₂/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 B₂O₃-SnO₂/C porous composites is controlled by diffusion and capacitance behavior, and the contribution rate of capacitance control increases with the increase of scan rate.