Effects of Additives on the Stability of Positive Electrolytes for All-Vanadium Redox Flow Battery

The all- Vanadium redox flow battery (VRFB) is a promising technology for large-scale electrical energy storage systems[1, 2]. VRFB is an electrochemical system using reactions of two redox couples of V 2+ /V 3+ in a negative half-cell and VO 2+ /VO 2 + in a positive half-cell to perform a reversible conversion between electrical energy and chemical energy. However, poor stability of the electrolytes, especially the positive electrolyte, greatly limits the concentration of redox couples in the electrolyte solution, which significantly affects the performance of VRFBs[3, 4]. In order to achieve high electrolyte performance, a sodium pyrophosphate dibasic (SPD) introduced as an inorganic additive in positive electrolyte VO 2 + for VRFBs. And its effects on long-term stability and electrochemical performances were investigated, through UV-vis spectrophotometry, cyclic voltammetry, and through the performance of a charge/discharge test. [1] A. Parasuraman, T.M. Lim, C. Menictas, M. Skyllas-Kazacos, Review of material research and development for vanadium redox flow battery applications, Electrochimica Acta, 101 (2013) 27-40. [2] A.Z. Weber, M.M. Mench, J.P. Meyers, P.N. Ross, J.T. Gostick, Q. Liu, Redox flow batteries: a review, Journal of Applied Electrochemistry, 41 (2011) 1137-1164. [3] J. Zhang, L. Li, Z. Nie, B. Chen, M. Vijayakumar, S. Kim, W. Wang, B. Schwenzer, J. Liu, Z. Yang, Effects of additives on the stability of electrolytes for all-vanadium redox flow batteries, Journal of Applied Electrochemistry, 41 (2011) 1215-1221. [4] S.-K. Park, J. Shim, J.H. Yang, C.-S. Jin, B.S. Lee, Y.-S. Lee, K.-H. Shin, J.-D. Jeon, Effect of inorganic additive sodium pyrophosphate tetrabasic on positive electrolytes for a vanadium redox flow battery, Electrochimica Acta, 121 (2014) 321-327.