石墨烯/炭黑杂化材料：新型、高效锂离子电池二元导电剂

摘要

采用CTAB为表面活性剂将氧化石墨烯和炭黑均匀分散,经水热过程将二者组装到一起,进而高温热处理得到石墨烯/炭黑杂化材料。该材料是一种具有独特结构和良好性能的石墨烯/炭黑杂化材料作为锂离子电池二元导电剂。炭黑颗粒均匀分布在石墨烯表面,可防止石墨烯片层团聚并进一步提高电子导电效率。由于炭黑可增加对电解液的吸附,促进电极内部锂离子的传输过程,最终提高锂离子电池的倍率性能。结果表明,使用质量分数5%900℃热处理之后的二元导电剂的LiFePO4,在10 C时比容量为73 mAh/g,优于使用10%炭黑导电剂时的LiFePO4(10 C比容量为62 mAh/g)。按照整个电极质量计算,前者的比容量性能比后者提高了近25%,同时在循环性能方面,前者的稳定性也优于后者。%A novel graphene( GN)/carbon black( CB) binary conductive additive has been developed, which is characterized by a unique microstructure and excellent performance for lithium ion batteries ( LIBs) . It was fabricated using a hydrothermal process, followed by heat treatment. The introduction of CB particles prevents GN from agglomerating and hence improves the electronic conductivity of the resulting additive. CB particles can also enhance the Li+ ion diffusion, owing to a reduction of the GN fraction and an increase in electrolyte adsorption. Therefore, the rate performance of the LIB is improved to some extent. Experimental data shows that the specific capacity of LiFePO4 containing 5% of this binary conductive additive ( after 900 ℃ treatment) is 73 mAh/g at 10 C, which is superior to that of LiFePO4 with 10% of CB (62 mAh/g). Compared with the latter, the former has a specific capacity increase of 25% based on the mass of the whole electrode and shows superior cycle stability.