Ultrahigh-Voltage LiCoO2 at 4.7 V by Interface Stabilization and Band Structure Modification,Advanced Materials

当前位置： X-MOL 学术 › Adv. 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.)

Ultrahigh-Voltage LiCoO2 at 4.7 V by Interface Stabilization and Band Structure Modification
Advanced Materials ( IF 27.4 ) Pub Date : 2023-02-27 , DOI: 10.1002/adma.202212059
Zhaofeng Zhuang ₁ , Junxiong Wang ₁ , Kai Jia ₁ , Guanjun Ji ₁ , Jun Ma ₁ , Zhiyuan Han ₁ , Zhihong Piao ₁ , Runhua Gao ₁ , Haocheng Ji ₁ , Xiongwei Zhong ₁ , Guangmin Zhou ₁ , Hui-Ming Cheng _{2,

3}

Affiliation

Lithium cobalt oxide (LCO) is widely used in Li-ion batteries due to its high volumetric energy density, which is generally charged to 4.3 V. Lifting the cut-off voltage of LCO from 4.3 V to 4.7 V will increase the specific capacity from 150 to 230 mAh g^-1 with a significant improvement of 53%. However, LCO suffers serious problems of H1-3/O1 phase transformation, unstable interface between cathode and electrolyte, and irreversible oxygen redox reaction at 4.7 V. Herein, interface stabilization and band structure modification are proposed to strengthen the crystal structure of LCO for stable cycling of LCO at an ultrahigh voltage of 4.7 V. Gradient distribution of magnesium and uniform doping of nickel in Li layers inhibit the harmful phase transitions of LCO, while uniform LiMg_xNi₁₋_xPO₄ coating stabilizes the LCO-electrolyte interface during cycles. Moreover, the modified band structure improves the oxygen redox reaction reversibility and electrochemical performance of the modified LCO. As a result, the modified LCO has a high capacity retention of 78% after 200 cycles at 4.7 V in the half cell and 63% after 500 cycles at 4.6 V in the full cell. This work makes the capacity of LCO one step closer to its theoretical specific capacity.

中文翻译：

通过界面稳定和能带结构修饰在 4.7 V 下的超高压 LiCoO2

钴酸锂（LCO）体积能量密度高，一般充电至4.3V，因此被广泛应用于锂离子电池中。将LCO的截止电压从4.3V提升至4.7V，比容量将从150 至 230 mAh g ^-1显着提高了 53%。然而，LCO 存在 H1-3/O1 相变、正极与电解质界面不稳定以及 4.7 V 下不可逆氧氧化还原反应等严重问题。在此，提出了界面稳定化和能带结构修饰来强化 LCO 的晶体结构以实现稳定LCO 在 4.7 V 的超高压下循环。Li 层中镁的梯度分布和镍的均匀掺杂抑制了 LCO 的有害相变，而均匀的 LiMg _x Ni₁₋_x PO ₄涂层在循环过程中稳定 LCO-电解质界面。此外，改性后的能带结构提高了改性LCO的氧氧化还原反应可逆性和电化学性能。因此，改进后的 LCO 在半电池中以 4.7 V 循环 200 次后容量保持率高达 78%，在全电池中以 4.6 V 循环 500 次后容量保持率为 63%。这项工作使 LCO 的容量更接近其理论比容量。

更新日期：2023-02-27

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