Aqueous potassium ion batteries (APIBs) are safe, robust, and environmentally friendly energy storage equipments. In this work, a high performance K+/OH− hybrid ion aqueous battery, using Co–Ni(OH)2 as the cathode and poly(1,4-anthraquinone) (P14AQ) as the anode, is proposed and characterized. By tuning the polymerization degree of P14AQ, the P14AQ/Co–Ni(OH)2 battery delivers a high energy/power density of 93 W h kg−1 at 1040 W kg−1 with an improved cycle life. Moreover, this P14AQ/Co–Ni(OH)2 battery shows a wide temperature operation window ranging from −30 °C to 25 °C. This proposed system is expected to be a promising battery for large-scale energy storage.
