炭含量对MoS_(2)/GR复合电极材料电化学性能的影响

Effect of carbon content on the electrochemical performance of MoS_(2)/GR composite electrode materials

将Hummers法制备石墨烯产生的副产物经过高温炭化和氢氧化钾(KOH)活化后得到石墨烯残留炭(GR)。以GR、钼酸钠及硫脲为原料,在pH=3的前置溶液中,通过简单的一步水热法制备了二硫化钼/石墨烯残留炭(MoS_(2)/GR)复合电极材料。通过改变GR的加入量(5%、10%、15%),探究其对MoS_(2)/GR电化学性能的影响。采用X射线衍射仪、扫描电子显微镜、电化学工作站对复合电极材料的结构、形貌及电化学性能进行表征和测试。结果表明:GR的加入会降低MoS_(2)的结晶度;随着GR加入量的增加,MoS_(2)/GR的尺寸会逐渐减小。当GR加入量为15%(质量分数)时,制备的样品15MoS_(2)/GR具有最高的比电容(312.0F/g),相较于纯MoS_(2)(110F/g)比电容提升了近3倍,并且在5A/g电流密度下循环1000次后,容量保持率为96.3%,表现出良好的循环稳定性。定量动力学计算表明,15MoS_(2)/GR的储能方式以扩散贡献为主。

Graphene residual carbon(GR) was obtained via high temperature charring and potassium hydroxide(KOH) activation of the by-products from graphene preparation by Hummers method.Using GR,sodium molybdate and thiourea as raw materials, the molybdenum disulphide/graphene residual carbon(MoS_(2)/GR) composite electrode material was prepared by a simple one-step hydrothermal method in a pH=3 pre-solution.The effect of the addition of GR on the electrochemical properties of MoS_(2)/GR was investigated by varying the amount of graphene GR(5%,10% and 15%).The structure, morphology and electrochemical properties of the composite electrode materials were characterised and tested by X-ray diffractometer, scanning electron microscope and electrochemical workstation.The results showed that the addition of GR reduced the crystallinity of MoS_(2)and the size of MoS_(2)/GR decreased with the increase of GR addition.When GR of 15% mass fraction was added, the prepared sample 15MoS_(2)/GR had the highest specific capacitance of 312.0F/g, which was nearly 3 times higher than that of pure MoS_(2)(110F/g).It also presented a good cycling stability with a capacity retention rate of 96.3% after 1000 cycles at a current density of 5A/g.Quantitative kinetic calculations revealed that the energy storage of 15MoS_(2)/GR was dominated by a diffusion contribution.