Progressive “Layer to Hybrid Spinel/Layer” Phase Evolution with Proton and Zn<sup>2+</sup> Co-intercalation to Enable High Performance of MnO<sub>2</sub>-Based Aqueous Batteries
Shouxiang Ding, Lele Liu, Runzhi Qin, Xin Chen, Aoye Song, Jiawen Li, Shunning Li, Qinghe Zhao, Feng Pan
Abstract
Manganese oxides are promising host materials in rechargeable aqueous batteries due to their low cost and high capacity; however, their practical applications have long been restricted by their sluggish reaction kinetics and poor cycling stability. Herein, the layered K0.36H0.26MnO2·0.28H2O (K36) with a proton and Zn2+ cointercalation mechanism leads to a progressive phase evolution from layer-type K36 to hybrid layer-type KxHyZnzMnO2·nH2O and spinel-type ZnMn2O4 nanocrystal after a long-term cycle. Accordingly, K36 shows a high specific capacity (∼329.8 mAh g–1 at 0.1C), a superior rate performance (∼100.1 mAh g–1 at 10C), and a remarkable cycling stability (capacity retention of ∼93.4% over 3000 cycles at 4C). This work provides a new viewpoint of enhancing electrode performance via generating hybrid phases under electrochemical driving and will be a benefit to developing the next-generation aqueous batteries.