Research progress in solid-state synthesized LiMnPO4 cathode material for Li-ion battery applications

Abstract

LiMnPO4 cathode material and its derivatives are promising for energy-storage devices owing to its environmental friendliness, high energy density, and structural stability. Olivine LiMnPO4 is attractive due to its high operating voltage (4 to 5 V vs. Li+/Li), and strong P-O covalent bond, which offers many safety advantages. Despite these advantages, the commercialization of LiMnPO4-based lithium-ion batteries (LIB) has been plagued by other factors such as poor electronic and ionic conductivity, a high surface energy barrier for Li-ion diffusion, and structural degradation induced by the Jahn-Teller effect. Various strategies, including transition metal doping at the A-site and the fabrication of heterostructures with high electron mobility, have been employed to address these challenges. Notably, the exceptional electrode performance of microrods may be ascribed to their distinct three-dimensional porous hierarchical structure, which promotes rapid Li+ transport kinetics and improves structural stability in reversible electrochemical reactions. While these enhancement techniques are centered on processing, solid-state chemistry is more effective, offering convenience in overcoming obstacles related to physiochemical and electrochemical performance. The solid-state synthesis approach, typically known for its capability to tailor the size and morphology of materials, has demonstrated a significant impact on enhancing the electrochemical activity of LiMnPO4. This review critically discusses the structure dependence of LiMnPO4 cathode material on electrochemical reactions. It gives a broad overview of the research approaches being employed to enhance the structure and electrochemical performance of LiMnPO4 through the solid-state technique. It also provides a comprehensive overview of the challenges and the need for further research to fully realize the potential of LiMnPO4 cathodes as a promising cathode material for Li-Ion batteries.