A Superior δ-MnO2 Cathode and a Self-Healing Zn-δ-MnO2 Battery.

By Donghong Wang, Lufeng Wang, Guo-jin Liang, Hongfei Li, Zhuoxin Liu, Zijie Tang, Jianbo Liang, Chunyi Zhi. ACS Nano, 2019

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While ɑ-MnO2 has been intensively studied for zinc batteries, δ-MnO2 is usually believed to be more suitable for ion storage with its layered structure. Unfortunately, the extraordinary Zn ion storage performance that δ-MnO2 should exhibit has yet not been achieved due to the frustrating structural degradation during charge-discharge cycles. Here, we found the Na ion and water molecules pre-intercalation can effectively activate stable Zn ion storage of δ-MnO2. Our results reveal that the resulted Zn//pre-intercalated δ-MnO2 battery delivers an extraordinarily high-rate performance, with a high capacity of 278 mAh g-1 at 1 C and up to 20 C, a high capacity of 106 mAh g-1 can still be measured. The capacity retention is as high as 98 % after charged-discharged up to 10000 cycles benefiting from smooth Zn ion diffusion in the pre-intercalated structure. Further in-situ/ex-situ characterization confirms the superfast Zn ion diffusion in the pre-intercalated structure at room temperature. In addition, utilizing the well-chosen electrode material and modified polyurethane shell, we fabricated a quasi-solid-state healable Zn-δ-MnO2, which can be self-healed after multiple catastrophic damages, emphasizing the advanced features of aqueous Zn ion battery for wearable applications.

Subfields: Electrical and Electronic Engineering, Electronic, Optical and Magnetic Materials

View Paper: https://www.semanticscholar.org/paper/f65527d9b3bc28f9c2140d38bc9e494774a97d0f