Tin/vanadium redox electrolyte for battery-like energy storage capacity combined with supercapacitor-like power handling

Abstract

We introduce a high performance hybrid electrochemical energy storage system based on an aqueous electrolyte containing tin sulfate (SnSO₄) and vanadyl sulfate (VOSO₄) with nanoporous activated carbon. The energy storage mechanism of this system benefits from the unique synergy of concurrent electric double-layer formation, reversible tin redox reactions, and three-step redox reactions of vanadium. The hybrid system showed excellent electrochemical properties such as a promising energy capacity (ca. 75 W h kg⁻¹, 30 W h L⁻¹) and a maximum power of up to 1.5 kW kg⁻¹ (600 W L⁻¹, 250 W m⁻²), exhibiting capacitor-like galvanostatic cycling stability and a low level of self-discharging rate.