Highlights An integrated conjugated microporous polymer composite electrode (C4N/rGO) with high conductivity, large specific surface area and good solvent resistance was prepared by in-situ growth. An antifreeze alkaline electrolyte (0.1 DMSO/2 M NaOH) was developed to broaden the operation temperature zone and voltage window of the aqueous alkaline battery. The prepared aqueous alkaline battery exhibits a high energy density (147.3 Wh Kg−1 at 25 °C), outstanding long cycling stability and excellent wide-temperature-range performance (−70 to 45 °C).