2.5 V “water in salt” aqueous micro-supercapacitors based on polypyrrole-coated NiCo layered double hydroxides

•3D indium tin oxide nanowires (ITO NWs) are fabricated by CVD.•The PPy shell prevents NiCo-LDH agglomeration and shedding.•PPy@NiCo-LDH@ITO NWs//PPy@FeOOH@ITO NWs asymmetric MSCs are assembled.•The MSCs achieve a voltage window of 0–2.5 V in a “water in salt” electrolyte.•The MSCs perform outstanding cyclic lifespan and volumetric energy density.