为了系统分析石墨烯正极材料中含氧官能团的量对材料电化学性能的影响,通过氧化石墨的低温膨胀法及后处理手段制备出3种不同官能团含量的石墨烯粉体材料,并进行了系统的理化表征和电化学性能表征。结果表明,当石墨烯材料用作锂离子电容器正极时,在其比表面积略微降低的前提下,若氧原子摩尔分数提高约14.5%,可逆比容量提升约13.4%;若氧原子摩尔分数降低约79%,可逆比容量降低约80.1%。说明含氧官能团的量是影响材料可逆比容量的关键因素。将此类石墨烯正极材料应用于软包型锂离子电容器器件中,器件表现出较好的电化学特性(在60 C充放电倍率下,器件容量保持率仍有47%)。

In order to systematically analyze the influence of the content of oxygen-containing functional groups in graphene cathode material on the electrochemical performance of the material,three graphene samples with different functional group contents are prepared via the low-temperature expansion method of graphite-oxide and post-processing methods,and physicochemical and electrochemical characterizations are carried out.The results show that the reversible specific capacity is increased by around 13.4% if the mole fraction of oxygen atom is increased by about 14.5% when the specific surface area of the graphene cathode material for lithium ion capacitors is slightly reduced.The reversible specific capacity drops by around 80.1% if the mole fraction of oxygen atom is reduced by about 79%.It demonstrates that the content of oxygen-containing functional groups is the key factor affecting the reversible specific capacity of the material.The graphene cathode material is also applied to the soft-packed lithium-ion capacitor that can provide satisfactory electrochemical properties,for example,the capacity retention is still 47% at 60 C charge/discharge rate.

宗军(1987-),男,博士,高级工程师,研究方向为储能材料及相关储能体系研究,zongjun2007@126.com。