生物基碳载硫正极材料的性能

Performance of biomass-derived carbons/sulfur cathode materials

采用具有超精细网络结构、良好分子取向、高结晶度和高聚合度等特性的细菌纤维素(BC)为基体碳源,通过添加KOH活化剂,在300℃预碳化2 h后,再在900℃碳化2 h,制备氮掺杂的具有较高比表面积(1 479 m^2/g)、孔分布范围广(0.2~5.0 nm)的分层次多孔碳纤维材料(NPC)。将硫单质通过熔融注入到NPC孔洞中,获得S-NPC复合材料。以复合正极材料组装电池,在1.5~2.7 V充放电,0.1 C首次放电比容量达1 137 mAh/g,经500次循环,比容量为890 mAh/g。平均每次循环,容量仅衰减约0.1%,且库仑效率高于98%。

Using bacterial cellulose （BC） with ultra-fine network structure, excellent molecular orientation, high crystallinity and degree of polymerization as the base carbon source, the nitrogen-doped hierarchical porous carbon fiber material （NPC） was prepared,which had a relatively high specific surface area （1 479 m2/g） and a large pore distribution （0.2 -5.0 nm） by precarbonization at 300 ℃ for 2 h with the addition of KOH activator and followed by 900 ℃ carbonization for 2 h. S-NPC composites were obtained by melting sulfur into NPC pores. The S-NPC composite as the cathode exhibited an initial specific discharge capacity of 1 137 mAh/g at 0. 1 C in 1.5 - 2. 7 V. It still maintained 890 mAh/g after 500 cycles. The average decay rate in a cycle was only 0. 1% , the Coulombic efficiency was above 98 %.