熵-相协同策略实现高性能高稳定性钠离子电池层状氧化物正极

摘要：面向规模化储能的需求，钠离子电池正极材料迫切需要同时兼顾高倍率与长寿命，并具备良好的空气稳定性以降低制造与封装成本。本文，四川轻化工大学陈建教授和成都理工大学龙剑平教授/胡安俊研究员等在《Chemical Engineering Journal》期刊发表名为“

1成果简介

面向规模化储能的需求，钠离子电池正极材料迫切需要同时兼顾高倍率与长寿命，并具备良好的空气稳定性以降低制造与封装成本。本文，四川轻化工大学陈建教授和成都理工大学龙剑平教授/胡安俊研究员等在《Chemical Engineering Journal》期刊发表名为“Entropy-phase synergy enables stable and high-rate layered oxide cathodes for sodium-ion batteries”的论文。本研究创新性地提出了“熵-相协同”的设计理念，通过巧妙的多元素协同掺杂与复合相调控，制备了高熵 P2/O3 双相层状正极 Na₀.₈Li₀.₀₅Co₀.₀₅Ni₀.₂Fe₀.₂Mn₀.₄Ti₀.₁O₂（简称LCNFMT）。

多元高熵构型协同扩大 Na层间距、收缩过渡金属层并抑制不利相变（O3-P3、P2-O2），显著提升 Na⁺扩散与结构稳定性，在0.1C下初始容量 170.3 mAh g⁻¹；1C 循环 300 圈后容量保持率 71.5%；8C 1000 圈后保持率 82.16%。在 60% 的空气湿度环境暴露 7天后结构变化极小，仅有少量碳酸盐生成，循环性能基本保持；同时通过全电池组装验证了其实际应用价值。本研究为设计开发下一代高性能、低成本的钠离子电池提供了新的思路。

2图文导读

图1. (a) Computational prediction of the target material's cation affinity prior to synthesis. XRD Rietveld refinement results of (b) LCNFMT and (c) NFM. Crystal parameters of LCNFMT (d)interlayer spacing and (e)bond length. (f) High-resolution transmission electron microscopy (HRTEM) images and corresponding signal profiles of the regions marked with blue and orange boxes in the LCNFMT (blue square corresponds to O3 phase, orange square corresponds to P2 phase). (g) Energy dispersive spectroscopy (EDS) elemental mapping of LCNFMT.

图2.(a) The initial charge-discharge profiles of LCNFMT, O3-HE, P2-HE and NFM at 0.1C. (b)Cycling performance at 1C. (c)The rate performance at different current densities. (d) Long-term cycling retention of NFM and LCNFMT at 8C. (e) EIS spectra for both cathodes in the pristine state and after 1000 cycles. (f) Variable scan rate CV curves from 0.2 to 1.0 mV s−1 of LCNFMT. (g) The linear fitting results for the absolute peak current intensity (Ip) as a function of the square root of the scan rate (v1/2) for NFM and LCNFMT. (h) Charged/discharged GITT curves and corresponding calculated DNa+of NFM and LCNFMT.(i) Long-term cycling retention of LCNFMT at 30C 。

图3. (a)Ni 2p, (b) Fe 2p, (c) Mn 2p XPS spectra of NFM and LCNFMT. (d) Li 1s (e)Co 2p, (f) Ti 2p, XPS spectra of LCNFMT.

图4. Operando XRD contour mappings visualizing the phase transitions of (a) LCNFMT and (b) NFM cathodes, integrated with their respective temporal c-axis parameter evolutions and associated voltage curves. (c)Comparison of c-axis evolution in NFM and LCNFMT during charging/discharging. XRD comparison before and after 1000 cycles of (d) LCNFMT and (e) NFM.

图5.Density of states (DOS) of a) NFM and b) LCNFMT. c) Ni(3deg*) of NFM and LCNFMT. Charge density difference plots of d) LCNMFT and e) NFM along the Z-axis direction.

图6.(a) XRD comparison and (b) FT-IR spectra of both cathodes after 7 days of exposure. (c) cycling performance of pristine and exposed cathodes. (d) Comparison between Na-storage cathode materials in this work and the previously reported exhibiting high rate performance. (e)Schematic representation of the full cell. (f) Initial charge–discharge curves at 1C within a voltage range of 2.0-4.3 V for the full cell. (g) Rate capability of the full cell. (h) Cycling performance of the full cell at 1C.

3小结

本文通过高熵组分设计和P2/O3双相工程，构筑了稳定且高倍率的层状氧化物钠离子电池正极 Na₀.₈Li₀.₀₅Co₀.₀₅Ni₀.₂Fe₀.₂Mn₀.₄Ti₀.₁O₂。其优异的电化学表现来源于“高熵×双相”的协同效应：抑制充放电过程中的不利相变（O3→P3、P2→O2），强化 Ni–O 键与 Na⁺扩散通道，实现离子动力学与结构稳定性的同步优化。最佳样品在 0.1C 下初始容量 170.3 mAh g⁻¹；1C 循环 300 圈容量保持率 71.5%；8C 循环 1000 圈仍保持 ≈82.2%。材料具备良好空气稳定性（60% 空气湿度暴露 7 天结构与性能基本保持），并在与硬碳组装的全电池中实现 ≈2.44 V 平均工作电压与约403.1 Wh kg⁻¹ 能量密度（1C、200 圈保持率 ≈67.5%），验证了潜在实用价值。本研究为开发快充、长寿命的钠离子电池正极提供了新思路。

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