摘要
Currently,the iron chromium redox flow battery(ICRFB)has become a research hotspot in the energy storage field owing to its low cost and easily-scaled-up.However,the activity of electrolyte is still ambiguous due to its complicated solution environment.Herein,we performed a pioneering investigation on the coordination behavior and transformation mechanism of Cr^(3+)in electrolyte and prediction of impurity ions impact through quantum chemistry computations.Based on the structure and symmetry of electrostatic potential distribution,the activity of different Cr^(3+)complex ions is confirmed as[Cr(H2O)5Cl]^(2+)>[Cr(H2O)4Cl2]+>[Cr(H2O)6]^(3+).The transformation mechanism between[Cr(H2O)6]^(3+)and[Cr(H2O)5Cl]^(2+)is revealed.We find the metal impurity ions(especially Mg^(2+))can exacerbate the electrolyte deactivation by reducing the transformation energy barrier from[Cr(H2O)5Cl]^(2+)(24.38 kcal mol^(−1))to[Cr(H2O)6]^(3+)(16.23 kcal mol^(−1)).The solvent radial distribution and mean square displacement in different solvent environments are discussed and we conclude that the coordination configuration limits the diffusivity of Cr^(3+).This work provides new insights into the activity of electrolyte,laying a fundamental sense for the electrolyte in ICRFB.
基金
Fundamental Research Funds for the Central Universities(2023MS125)。
