Li Xiang, Wang Kexin, Tian Miao, Zhang Xu, Wu Xingyang, Song Haotian, Yang Shuo-Wang, Zheng Junwei, Du Fanghui, Lyu Jing, Hao Zhongkai, Xu Guo Qin
Department of Chemistry, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore.
National University of Singapore (Chongqing) Research Institute, Chongqing, 401123, China.
Angew Chem Int Ed Engl. 2025 Jul;64(29):e202504221. doi: 10.1002/anie.202504221. Epub 2025 May 24.
The growing demand for high-energy-density cathode is pushing LiCoO towards 4.6 V operation. However, the structural and interfacial instability of high-voltage LiCoO is exacerbated when the charging cut-off voltage exceeds 4.55 V, resulting in severe mechanical failure and subsequent dramatic capacity decay. Herein, through thermally driven element interdiffusion, a highly durable Co-containing Li-rich phase with the lattice coherence has been epitaxially grown along LiCoO surface, which enhances the intrinsic mechanical integrity of high-voltage LiCoO. Through establishing the lattice-coherent Li-rich surface, adverse side reactions, irreversible phase transition and lattice oxygen loss are significantly inhibited in high-voltage LiCoO, thereby alleviating cracks formation and maintaining the structural integrity. The presence of the Li-rich phase endows LiCoO with the additional capacity and the excellent cycling stability at 4.6 V and even at 4.7 V. This work taps into a new avenue of surface engineering on high-voltage LiCoO.
对高能量密度阴极不断增长的需求正推动着钴酸锂向4.6伏的工作电压发展。然而，当充电截止电压超过4.55伏时，高压钴酸锂的结构和界面不稳定性会加剧，导致严重的机械故障以及随后显著的容量衰减。在此，通过热驱动的元素相互扩散，一种具有晶格相干性的高耐久性含钴富锂相已沿钴酸锂表面外延生长，这增强了高压钴酸锂的固有机械完整性。通过建立晶格相干的富锂表面，在高压钴酸锂中，不利的副反应、不可逆的相变和晶格氧损失得到了显著抑制，从而减轻了裂纹的形成并保持了结构完整性。富锂相的存在赋予了钴酸锂额外的容量以及在4.6伏甚至4.7伏时出色的循环稳定性。这项工作开辟了一条关于高压钴酸锂表面工程的新途径。
