钒电池负极电解液V_2(SO_4)_3溶解性规律

Solubility Rules of Negative Electrolyte V_2(SO_4)_3 of Vanadium Redox Flow Battery

对钒电池负极电解液中活性物质V（Ⅲ）在不同硫酸浓度、不同温度条件下的溶解性规律进行了深入研究，同时对VOID-H2S04体系电化学性能进行了初步探讨．结果表明：V（Ⅲ）的溶解是一个放热过程，在15。40℃范围内，V（111）的溶解度随着温度升高而逐渐降低；并且溶液中VOID会以V-O-V形式形成二聚体，在低硫酸浓度下，V（Ⅲ）可以高浓度长时间稳定存在，随硫酸浓度的增大，V（Ⅲ）溶解度逐渐降低，其中30℃、1mol／LH2s04条件下V（Ⅲ）浓度可高达2．730mol／L；进一步通过电化学测试，发现V（Ⅲ）-H2S04体系是不可逆体系，H2S04浓度的增大有益于提高V（Ⅲ）/V（Ⅱ）氧化还原反应的可逆性．

The solubility of V（Ⅲ） species in negative electrolyte of all vanadium redox flow battery （VRB） was studied and the solubility parameters of V（Ⅲ） species at various concentrations of H2SO4 and different temperatures were preliminarily obtained. The results showed that dissolution of V（Ⅲ） was an exothermic process. The solubility of V（Ⅲ） decreased with temperature （15-40℃）. Also, the presence of V（Ⅲ） in the solution was a V-O-V dimmer. The solubility of V（Ⅲ） decreased with the increasing of I＇-I2504 and low concentration of H2SO4 would keep high concentration of V（Ⅲ） stable for a long time. Especially, concentration of V（Ⅲ） could reach 2.730 mol/L with 1 mol/L H2SO4 at 30℃. Electrochemical properties was further investigated by experiment, the results revealed that V（III）-H2SO4 solution was an irreversible system for V（Ⅲ）/V（Ⅱ） redox reaction. Increasing of concentration of H2SO4 had zreat benefit to imorove the reversibility of V（Ⅲ）/V（II） redox reaction.