Aqueous Rechargeable Alkaline Co_<i>x</i>Ni_2–<i>x</i>S₂/TiO₂ Battery

Abstract

An electrochemical energy storage\nsystem with high energy density,\nstringent safety, and reliability is highly desirable for next-generation\nenergy storage devices. Here an aqueous rechargeable alkaline Co_<i>x</i>Ni_2–<i>x</i>S₂ // TiO₂ battery system is designed by integrating\ntwo reversible electrode processes associated with OH^– insertion/extraction in the cathode part and Li ion insertion/extraction\nin the anode part, respectively. The prototype Co_<i>x</i>Ni_2–<i>x</i>S₂ // TiO₂ battery is able to deliver high energy/power densities of\n83.7 Wh/kg at 609 W/kg (based on the total mass of active materials)\nand good cycling stabilities (capacity retention 75.2% after 1000\ncharge/discharge cycles). A maximum volumetric energy density of 21\nWh/l (based on the whole packaged cell) has been achieved, which is\ncomparable to that of a thin-film battery and better than that of\ntypical commercial supercapacitors, benefiting from the unique battery\nand hierarchical electrode design. This hybrid system would enrich\nthe existing aqueous rechargeable LIB chemistry and be a promising\nbattery technology for large-scale energy storage.