Comprehensive analysis of improved LiFePO4 kinetics: Understanding barriers to fast charging

Abstract

Lithium iron phosphate (LFP) is an outstanding cathode material for lithium-ion batteries due to its thermal stability, safety, and cost-effectiveness. However, its practical application is limited by the material's intrinsically low electronic conductivity and lithium-ion diffusion coefficient, which restrict its rate capability. This review comprehensively examines various strategies developed to enhance the electrochemical performance of LFP, focusing on both individual and combined improvements in ionic and electronic conductivities. We analyze the impact of particle size and morphology, dopants, conductive additives, and carbon coatings on the material's diffusion coefficient and electronic conductivity, supported by an exhaustive compilation of data from literature. Additionally, we discuss the potential of these strategies to synergistically enhance the specific capacity and rate capability of LFP. Special attention is given to advanced manufacturing techniques and the development of new material architectures aimed at optimizing the material's kinetic properties and minimizing inactive components. Our findings highlight the need for a holistic approach that integrates the most promising strategies into a unified LFP structure. We also emphasize the importance of comprehensive characterization, including electronic conductivity, ionic diffusivity, and specific capacity under various current rates, to provide a more complete understanding of the material's behavior. This review serves as a guide for future research directions, aiming to overcome current limitations and achieve the full potential of LFP in high-performance energy storage applications.