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<p>High‑nickel-layered oxides are promising candidates for high‑energy‑density batteries but are plagued by detrimental surface residual lithium generated during calcination. Herein, we propose a “Mn‑activated topological lithiation” strategy that achieves near-surface overlithiation and residual lithium mitigation via a one-step solid-state process without introducing additional lithium sources beyond those compensating for calcination losses. Using inexpensive MnO<sub>2</sub> as a coating agent, it combines with the lithium source on the preliminarily lithiated cathode surface to simultaneously achieve redundant lithium anchoring during the layered phase transition, forming an electrochemically active Li<sub>2</sub>NiO<sub>2</sub>-type cation-ordered superstructure. Moreover, we reveal a Mn‑concentration‑dependent phase evolution mechanism: Moderate Mn doping (2&#xa0;mol%) promotes the beneficial migration of Ni ions into the Li layer and induces near‑surface overlithiation, enabling the cathode to deliver a high specific capacity of 250.32 mAh g<sup>−1</sup> and a high initial coulombic efficiency of 92.24%. When the doping level increases to 3&#xa0;mol%, a conformal Li<sub>2</sub>MnO<sub>3</sub> coating is further formed, which suppresses intergranular cracking and endows the material with excellent lithium‑ion diffusion kinetics and interfacial stability. After 100 cycles at 0.5 C, the capacity retention reaches 159.41 mAh g<sup>−1</sup>, representing a 31.5% improvement over the pristine sample. This work demonstrates a feasible pathway to simultaneously eliminate surface impurities and reconstruct surface lattices for high-performance Li–ion batteries.</p> Graphical Abstract <p></p>

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Reconstruction of ultra-high nickel oxide cathode: converting excess lithium into active overlithiated superstructures via Mn-activated diffusion

  • 期刊论文

  • 发表日期：

    2026年4月8日

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  • Chaohui Chen,
  • Shan Jin,
  • Dehao Fu,
  • Yingxiang Zhong,
  • Haofeng Tan,
  • Junxia Meng,
  • Quanxin Ma

摘要

High‑nickel-layered oxides are promising candidates for high‑energy‑density batteries but are plagued by detrimental surface residual lithium generated during calcination. Herein, we propose a “Mn‑activated topological lithiation” strategy that achieves near-surface overlithiation and residual lithium mitigation via a one-step solid-state process without introducing additional lithium sources beyond those compensating for calcination losses. Using inexpensive MnO2 as a coating agent, it combines with the lithium source on the preliminarily lithiated cathode surface to simultaneously achieve redundant lithium anchoring during the layered phase transition, forming an electrochemically active Li2NiO2-type cation-ordered superstructure. Moreover, we reveal a Mn‑concentration‑dependent phase evolution mechanism: Moderate Mn doping (2 mol%) promotes the beneficial migration of Ni ions into the Li layer and induces near‑surface overlithiation, enabling the cathode to deliver a high specific capacity of 250.32 mAh g−1 and a high initial coulombic efficiency of 92.24%. When the doping level increases to 3 mol%, a conformal Li2MnO3 coating is further formed, which suppresses intergranular cracking and endows the material with excellent lithium‑ion diffusion kinetics and interfacial stability. After 100 cycles at 0.5 C, the capacity retention reaches 159.41 mAh g−1, representing a 31.5% improvement over the pristine sample. This work demonstrates a feasible pathway to simultaneously eliminate surface impurities and reconstruct surface lattices for high-performance Li–ion batteries.

Graphical Abstract