Advances in Co-free layered cathode materials for Li-ion batteries
Jianhua Ge, Min-yan Xie, Qunfang Zhao, Shuqiong Zhang, Hao Sun
Abstract
The cathode materials of Li-ion batteries have become one of the main factors hindering broader development of electric vehicles because cathode performances are unable to satisfy the growing demand for mileage, safety, and fast charging. In addition, the cost of commercial Co-bearing cathode materials has raised because of the scarcity and price of Co. As a result, promising substitutes such as Co-free Li-rich and Ni-rich layered materials have been proposed. However, these two materials suffer from intrinsic problems such as undesired phase transitions and poor conductivity. In recent years, great advances have been made in improving the performances of the two types of materials with various modification strategies, although some problems remain unsolved. Herein, we review the properties and drawbacks of these two types of materials and then summarizes and discusses the latest progress in improving their properties through optimized synthesis and modification methods. Finally, some perspectives regarding future research on Co-free layered cathode materials are presented. This timely review seeks to provide an overview of the latest research into eliminating the need for Co in layered cathode materials.