P-doping reinforces the crystal phase stability of α-MnO2 cathodes for aqueous zinc-ion batteries

Phosphorus-doped α-manganese dioxide cathode material was successfully synthesized. • P-α-MnO 2 possesses excellent electrochemical performance. • P doping can enhance structural stability of the α-MnO 2 phase. MnO 2 is recognized as a highly competitive cathode candidate for aqueous zinc-ion batteries (AZIBs) thanks to its low fabrication cost and considerable reversible capacity. However, MnO 2 suffers from severe manganese dissolution and structural phase transitions during cycling, leading to crystalline phase instability and thus severely limiting further performance enhancement of AZIBs. Herein, we successfully construct Phosphorus‑incorporated α‑MnO 2 (P-α-MnO 2 ) via an ion doping strategy and evaluate its electrochemical performance in AZIBs. PMO-2 delivers a peak capacity of 440.7 mAh g −1 at 0.1 A g −1 after 20 cycles and sustains 89% capacity (192–170.8 mAh g −1 ) upon 1500 cycles at 1.5 A g −1 , exhibiting better retention compared with pristine α-MnO 2 that maintains merely 49.6% (159–78.9 mAh g −1 ). Combined structural characterizations and DFT calculations indicate that the boosted performance of P-α-MnO 2 stems from phosphorus doping strengthening the crystalline stability of α-MnO 2 . It can substantially cut down Zn 2+ adsorption energy as well as ion‑migration barriers, which alleviates lattice‑channel destruction caused by Zn 2+ insertion‑extraction and preserves the tunnel‑type crystal framework of α‑MnO 2 throughout charge‑discharge operations. This work provides important theoretical foundations and design strategies for the further development of low-cost, high-stability, and high-energy-density manganese-based cathode materials. Download: Download high-res image (148KB) Download: Download full-size image