Short process for preparing high-purity vanadium electrolyte by efficient selective oxidation of vanadium from multi-impurity shale-hosted leachate via the synergistic effect of H2O2 and NaClO

In traditional methods for preparing vanadium electrolytes, challenges include lengthy processes, high costs, and difficulties in deeply separating vanadium and impurities. This study introduces an innovative approach utilizing an H 2 O 2 -NaClO efficient selective oxidative stripping system within the D2EHPA extraction process. This method was optimized at a pH of 12, with a phase ratio (O/A) of 6:1, a reaction temperature of 45 °C, and a reaction time of 8 min. The concentration of H 2 O 2 was set at 1.5 %, with a volume ratio between H 2 O 2 and NaClO of 95 % to 5 %. Under these conditions, the vanadium stripping rate in a single stage reached 95.13 %. The low concentration (1.5 %) of H 2 O 2 increased the single-stage stripping rate of vanadium by nearly 50 %, reducing H 2 O 2 usage by at least 25 %, while NaClO enhanced the stability of H 2 O 2 . The prepared electrolyte contained impurity ion concentrations of less than 10 ppm, meeting Chinese national first-class standard of Electrolyte for vanadium flow battery. The electrolyte demonstrated excellent electrochemical and charge–discharge performance, with Coulombic efficiency, voltage efficiency, and energy efficiency reaching 85.45 %, 89.58 %, and 76.55 %, respectively, achieving 95 % of the standard electrolyte’s performance. This method significantly shortens the process and reduces costs by 25.29 % compared to the traditional V 2 O 5 dissolution method. This study offers a novel approach to producing high-purity electrolytes through a shorter, cost-effective process.