摘要
为进一步认识石墨材料在钒电池集流体中的稳定性机理及其影响因素,探讨其作为钒电池关键材料的可行性,进行了循环伏安(CV)、充放电测试。结果表明,石墨在高浓度硫酸溶液中容易形成一阶石墨层间化合物(GIC),其在高电压下容易形成石墨氧化物(GO),使得钒离子在正极反应的可逆性遭到破坏,反应极化增大,电池的性能急剧下降。GO电极在3 mol/L硫酸的钒电解液中,负电位范围(-0.8～0 V)循环伏安扫描之后,生成了GO和还原的石墨氧化物(RGO)的混合物。用它作电极,在0～1.5 V的扫描电位范围内的第一个循环伏安曲线上出现了两个V(IV)的氧化峰,其中一个峰电位1.438 V(vs.SCE)对应的是电极的GO部分,另一个0.998 V(vs.SCE)对应的是电极的RGO部分,与1.438 V(vs.SCE)相比,负移了0.44 V。这与石墨氧化物和还原的石墨氧化物(RGO)的大π键共轭结构和电子导电性随O-C原子比的变化相关。
CV,charging/ discharging measurements were carried out to study the stability of graphite material in containing H2SO4 solutions during electrochemical processes and the related influencing factors, and the possibility of its use as current collector for vanadium redox flow battery was discussed. The results show that graphite in concentrated sulphuric acid solutions easily forms graphite intercalation compounds, and it＇s easy to form graphite oxide （GO） at high voltage. When GIC experiences the overoxidation in vanadium electrolyte, the reversibility of the positive reaction is destructed, and the polarization resistance increases. The contact resistance of the electrode and the current collector increases sharply because of the formed fluffy graphite oxide, so the performance of the battery is declining badly. After negative potential （-0.8-0 V） scanning of GO electrode in V（IV） 3 mol/L H2SO4 solution, it becomes a mixture of the unreduced graphite oxide （GO） and reduced graphite oxide （RGO）. Within the scanning potential range of 0-1.5 V, there are two oxidation peaks of V（IV） on the first cycle curve. One of the oxidation peak potentials is 1.438 V （vs. SCE）, corresponding to GO of the electrode, the other shows a negative shift of the peak potential to 0.998 V（vs. SCE） ,corresponding to RGO of the electrode. It is consistent with the intensity of π state and electronic conductivity of GO and RGO, which bear different O-C atomic rations.
出处
《电源技术》
CAS
CSCD
北大核心
2011年第12期1527-1529,1547,共4页
Chinese Journal of Power Sources
基金
"973"国家重点基础研究发展计划资金资助项目(2010CB227201)
国家自然科学基金(50972165)资助项目
关键词
钒电池
石墨
硫酸
石墨层间化合物(GIC)
稳定性
vanadium redox flow battery
graphite
sulphuric acid
graphite intercalation compound（GIC）
stability
