Zinc-doping strategy on P2-type Mn-based layered oxide cathode for high-performance potassium-ion batteries

Yunshan Zheng, Junfeng Li, Shunping Ji, Kwan San Hui, Shuo Wang, Huifang Xu, Kaixi Wang, Duc Anh Dinh, Chenyang Zha, Zongping Shao, Kwun Nam Hui

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12 Citations (Scopus)

Abstract

Mn-based layered oxide is extensively investigated as a promising cathode material for potassium-ion batteries due to its high theoretical capacity and natural abundance of manganese. However, the Jahn–Teller distortion caused by high-spin Mn3+(t2g3eg1) destabilizes the host structure and reduces the cycling stability. Here, K0.02Na0.55Mn0.70Ni0.25Zn0.05O2 (denoted as KNMNO-Z) is reported to inhibit the Jahn–Teller effect and reduce the irreversible phase transition. Through the implementation of a Zn-doping strategy, higher Mn valence is achieved in the KNMNO-Z electrode, resulting in a reduction of Mn3+ amount and subsequently leading to an improvement in cyclic stability. Specifically, after 1000 cycles, a high retention rate of 97% is observed. Density functional theory calculations reveals that low-valence Zn2+ ions substituting the transition metal position of Mn regulated the electronic structure around the Mn-O bonding, thereby alleviating the anisotropic coupling between oxidized O2− and Mn4+ and improving the structural stability. K0.02Na0.55Mn0.70Ni0.25Zn0.05O2 provided an initial discharge capacity of 57 mAh g−1 at 100 mA g−1 and a decay rate of only 0.003% per cycle, indicating that the Zn-doped strategy is effective for developing high-performance Mn-based layered oxide cathode materials in PIBs.

Original languageEnglish
Article number2302160
JournalSmall
Volume19
Issue number39
Early online date10 May 2023
DOIs
Publication statusPublished - 27 Sep 2023

Keywords

  • Jahn–Teller distortion
  • KNaMnNiZnO cathodes
  • Mn-based layered oxide
  • Zn-doping strategy

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