Earth-abundant Li-ion cathode materials with nanoengineered microstructures
Han‐Ming Hau, Tara P. Mishra, Colin Ophus, Tzu‐Yang Huang, Karen Bustilo, Yingzhi Sun, Xiaochen Yang, Tucker Holstun, Xinye Zhao, Shilong Wang, Yang Ha, Gi‐Hyeok Lee, Chengyu Song, John Turner, Jianming Bai, Lu Ma, Ke Chen, Feng Wang, Wanli Yang, Bryan D. McCloskey, Zijian Cai, Gerbrand Ceder
Abstract
Abstract Manganese-based materials have tremendous potential to become the next-generation lithium-ion cathode as they are Earth abundant, low cost and stable. Here we show how the mobility of manganese cations can be used to obtain a unique nanosized microstructure in large-particle-sized cathode materials with enhanced electrochemical properties. By combining atomic-resolution scanning transmission electron microscopy, four-dimensional scanning electron nanodiffraction and in situ X-ray diffraction, we show that when a partially delithiated, high-manganese-content, disordered rocksalt cathode is slightly heated, it forms a nanomosaic of partially ordered spinel domains of 3–7 nm in size, which impinge on each other at antiphase boundaries. The short coherence length of these domains removes the detrimental two-phase lithiation reaction present near 3 V in a regular spinel and turns it into a solid solution. This nanodomain structure enables good rate performance and delivers 200 mAh g −1 discharge capacity in a (partially) disordered material with an average primary particle size of ∼5 µm. The work not only expands the synthesis strategies available for developing high-performance Earth-abundant manganese-based cathodes but also offers structural insights into the ability to nanoengineer spinel-like phases.