全钒液流电池正极电解液离子结构理论探究

Theoretical Study on Ion Structure of Cathode Electrolyte for All Vanadium Flow Battery

通过量子力学的密度泛函理论(DFT)模拟,对全钒液流电池电解液中四、五价态钒离子的结构稳定性进行了系统地研究。本文以正极电解液V^(5+)和V^(4+)与V=O双键为基础,结合H_(2)O、HSO_(4)^(-)、SO_(4)^(2-)基团,根据拉曼光谱的结果、钒离子的价态、八面体配位结构的稳定性,设计了V(=O)(HSO_(4))(SO_(4))(H_(2)O)_(3)和V(=O)(SO_(4))(H_(2)O)_(4)结构。通过结构稳定性和氧化还原反应的模拟,对钒电池的储能机制提出了一个合理的解释。本文采用的模型和计算方式,对于其他类型钒离子在全钒液流电池的存在形式和作用具有借鉴意义,从而对全钒液流电池改性提供理论上的支持。

By the using of density functional theory(DFT)about the quantum chemistry,systematic study the stability of geometry about+4/+5 states vanadium ion in the vanadium flow battery electrolyte.Our work base on the V^(5+)和V^(4+)and V=O group in the cathode electrolyte,the H_(2)O,HSO_(4)^(-),SO_(4)^(2-)group arrangement and combination in the first shell of vanadium ion,connect with the Raman spectrum,states of vanadium ion and the stable of the octahedral coordination structure,design about the structure of V(=O)(HSO_(4))(SO_(4))(H_(2)O)_(3) and V(=O)(SO_(4))(H_(2)O)_(4).A reasonable explanation for the energy storage mechanism of vanadium flow battery,by the simulation of structure stability and the redox reaction.The using of our model and computed mode will have reference significance for the function and existence of another type vanadium ion in the vanadium flow battery.It provides theoretical support for modification vanadium flow battery.