Unexpectedly High Cycling Stability Induced by a High Charge Cut-Off Voltage of Layered Sodium Oxide Cathodes,Advanced Energy Materials

当前位置： X-MOL 学术 › Adv. Energy Mater. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Unexpectedly High Cycling Stability Induced by a High Charge Cut-Off Voltage of Layered Sodium Oxide Cathodes
Advanced Energy Materials ( IF 24.4 ) Pub Date : 2022-12-23 , DOI: 10.1002/aenm.202203216
Qiuyu Shen ₁ , Yongchang Liu _{1,

2} , Xudong Zhao ₃ , Junteng Jin ₁ , Xiaobai Song ₁ , Yao Wang ₁ , Xuanhui Qu ₁ , Lifang Jiao ₂

Affiliation

Initiating anionic redox chemistry in layered sodium oxide cathodes is a prevalent method to break the capacity limit set by traditional transition metal redox. However, realizing the “win-win” scenario of high capacity and high cycling stability is still challenging due to the high-voltage structural distortion and irreversible oxygen loss. Herein, a Mn activation mechanism is unveiled in a novel P2-Na_0.80Li_0.08Ni_0.22Mn_0.67O₂ cathode. By elevating the charge cut-off voltage to 4.3 V, anionic redox is successfully triggered and partial oxygen loss enables the reduction of Mn upon discharge, thus activating more Mn³⁺/Mn⁴⁺ redox reactions in the following cycles and maintaining the total capacity almost unchanged. In situ X-ray diffraction reveals a complete solid-solution reaction with an ultralow volume change of 1.04% upon cycling. Consequently, the P2-Na_0.80Li_0.08Ni_0.22Mn_0.67O₂ cathode simultaneously accomplishes a high discharge capacity (134.8 mAh g⁻¹ at 0.1 C) and an unexpectedly long cycling life (capacity retention of 91.5% and 85.2% after 500 and 1000 cycles at 10 C, respectively). Via systematic ex situ characterizations and theoretical computations, the charge compensation mechanism upon Na⁺ insertion/extraction is elucidated. This work broadens the horizons of current oxygen redox chemistry and provides a new path to design high-performance layered oxide cathode materials for sodium-ion batteries.

中文翻译：

层状氧化钠阴极的高充电截止电压诱导出乎意料的高循环稳定性

在层状氧化钠阴极中引发阴离子氧化还原化学反应是打破传统过渡金属氧化还原容量限制的一种普遍方法。然而，由于高压结构变形和不可逆的氧损失，实现高容量和高循环稳定性的“双赢”场景仍然具有挑战性。在此，揭示了新型 P2-Na _0.80 Li _0.08 Ni _0.22 Mn _0.67 O ₂阴极中的 Mn 活化机制。通过将充电截止电压提高到 4.3 V，成功触发阴离子氧化还原，部分氧损失使放电时 Mn 还原，从而激活更多的 Mn ³⁺ /Mn ⁴⁺在随后的循环中发生氧化还原反应并保持总容量几乎不变。原位 X 射线衍射揭示了一个完整的固溶体反应，在循环时具有 1.04% 的超低体积变化。因此，P2-Na _0.80 Li _0.08 Ni _0.22 Mn _0.67 O ₂正极同时实现了高放电容量（在 0.1 C 时为 134.8 mAh g ^-1）和出乎意料的长循环寿命（500 年后容量保持率分别为 91.5% 和 85.2%）分别在 10 C 下进行 1000 次循环）。^{通过系统的非原位表征和理论计算，Na +}的电荷补偿机制阐明了插入/提取。这项工作拓宽了当前氧氧化还原化学的视野，并为设计用于钠离子电池的高性能层状氧化物正极材料提供了一条新途径。

更新日期：2022-12-23

点击分享查看原文

点击收藏

阅读更多本刊新发论文本刊介绍/投稿指南