Modifying δ-MnO2 with unsaturated phosphate groups realizes fast kinetics and superior cyclability for aqueous zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) have emerged as a promising technology in the realm of large-scale energy storage, with cathode material performance being a critical determinant of their practical viability. Among various cathode material candidates, MnO 2 has garnered substantial attention, whereas it suffers from poor cyclability and sluggish reaction kinetics. Herein, an efficient approach is presented to address these challenges through the development of a phytic acid-modified δ-MnO 2 , fabricated through a one-step oil-bath strategy. In the composite, the phytic acid coating can mitigate MnO 2 dissolution, and the insertion of phytic acid with excellent zincophilicity can promote Zn 2+ ion intercalation and diffusion, hence significantly improving electrochemical kinetics and reversibility. Owing to these advantages, the modified MnO 2 offers a large specific capacity of 233.4 mAh g –1 at 0.2 A g –1 , and maintains 83.6 % and 48.2 % of that capacity as the current density rises to 1 and 5 A g –1 , respectively. Under a large mass loading of 10 mg cm –2 , this material exhibits outstanding cycling stability, retaining 90.4 % of its initial capacity after 1000 cycles. This work provides valuable insights into material engineering for advanced battery technologies.