Achieving high-energy and long-cycling aqueous zinc-metal batteries by highly reversible insertion mechanisms in Ti-substituted Na0.44MnO2 cathode

•The tunnel-type Ti-substituted Na0.44MnO2 was investigated as cathode for aqueous zinc batteries.•The Ti-substitution can efficiently improve the electrochemical kinetics with superior high-rate capability and cycling stability.•The facilitated reaction mechanism with stepwise Zn2+ and H+ insertions was versified.•The optimal Na0.44Mn0.78Ti0.22O2 material exhibits a high reversible capacity and a cycling life record for 2400 cycles.