Insights into layered–tunnel dynamic structural evolution based on local coordination chemistry regulation for high-energy-density and long-cycle-life sodium-ion oxide cathodes,InfoMat

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Insights into layered–tunnel dynamic structural evolution based on local coordination chemistry regulation for high-energy-density and long-cycle-life sodium-ion oxide cathodes
InfoMat ( IF 22.7 ) Pub Date : 2023-07-26 , DOI: 10.1002/inf2.12475
Yao Xiao _{1,

2,

3} , Yi‐Feng Liu _{1,

2,

4} , Hong‐Wei Li _{1,

2} , Jia‐Yang Li _{2,

5} , Jing‐Qiang Wang _{1,

2} , Hai‐Yan Hu _{1,

2} , Yu Su _{1,

2} , Zhuang‐Chun Jian _{1,

2} , Hu‐Rong Yao ₆ , Shuang‐Qiang Chen _{1,

2} , Xian‐Xiang Zeng ₄ , Xiong‐Wei Wu ₄ , Jia‐Zhao Wang _{2,

5} , Yan‐Fang Zhu _{1,

2} , Shi‐Xue Dou ₅ , Shu‐Lei Chou _{1,

2}

Affiliation

The pursuit of high energy density while achieving long cycle life remains a challenge in developing transition metal (TM) oxide cathode materials for sodium-ion batteries (SIBs). Here, we present a concept of precisely manipulating structural evolution via local coordination chemistry regulation to design high-performance composite cathode materials. The controllable structural evolution process is realized by tuning magnesium content in Na_0.6Mn_1−xMg_xO₂, which is elucidated by a combination of experimental analysis and theoretical calculations. The substitution of Mg into Mn sites not only induces a unique structural evolution from layered–tunnel structure to layered structure but also mitigates the Jahn–Teller distortion of Mn³⁺. Meanwhile, benefiting from the strong ionic interaction between Mg²⁺ and O²⁻, local environments around O²⁻ coordinated with electrochemically inactive Mg²⁺ are anchored in the TM layer, providing a pinning effect to stabilize crystal structure and smooth electrochemical profile. The layered–tunnel Na_0.6Mn_0.95Mg_0.05O₂ cathode material delivers 188.9 mAh g⁻¹ of specific capacity, equivalent to 508.0 Wh kg⁻¹ of energy density at 0.5C, and exhibits 71.3% of capacity retention after 1000 cycles at 5C as well as excellent compatibility with hard carbon anode. This work may provide new insights of manipulating structural evolution in composite cathode materials via local coordination chemistry regulation and inspire more novel design of high-performance SIB cathode materials.

中文翻译：

基于局部配位化学调控的高能量密度和长循环寿命钠离子氧化物阴极的层状隧道动态结构演化的见解

在实现长循环寿命的同时追求高能量密度仍然是开发钠离子电池（SIB）过渡金属（TM）氧化物正极材料的挑战。在这里，我们提出了通过局域配位化学调节精确操纵结构演化来设计高性能复合正极材料的概念。_{通过调节Na 0.6} Mn _{1− x} Mg _x O ₂中的镁含量实现了可控的结构演化过程，并通过实验分析和理论计算相结合阐明了这一过程。Mg 取代 Mn 位点不仅引发了从层状隧道结构到层状结构的独特结构演化，而且还减轻了 Mn ³⁺的 Jahn-Teller 畸变。^{同时，受益于Mg 2+}和O ²⁻之间的强离子相互作用，O ²⁻周围的局部环境与电化学不活泼的Mg ²⁺配合被锚定在TM层中，提供钉扎效应以稳定晶体结构和平滑的电化学曲线。层状隧道Na _0.6 Mn _0.95 Mg _0.05 O ₂正极材料的比容量为188.9 mAh g ^-1，相当于0.5C下的能量密度为508.0 Wh kg ^-1，并且在5C下循环1000次后容量保持率为71.3%以及与硬碳阳极优异的相容性。这项工作可能为通过局部配位化学调控来操纵复合正极材料的结构演化提供新的见解，并激发高性能SIB正极材料的更新颖的设计。

更新日期：2023-07-26

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