Anode interphase design for fast-charging lithium-based rechargeable batteries

Abstract

High energy density and exceptional fast-charging capability are emerging as critical technical parameters for lithium (Li)-based rechargeable batteries, aimed at meeting the increasing demands of advanced portable electronics, electric vehicles, and grid energy storage systems. However, the sluggish charge transfer kinetics associated with contemporary graphite anodes significantly hinder both the fast-charging performance and overall energy characteristics of existing Li-based rechargeable batteries. As we transition to high-capacity anodes (such as alloying-type and Li metal anodes) for next-generation high-energy-density batteries, their inherent slow electrochemical Li⁺/e⁻ combination rate presents new challenges for fast charging. Furthermore, the significant volume changes that occur during charge and discharge processes contribute to the structural instability of these high-capacity materials and electrodes. This phenomenon also leads to severe side reactions between the active material and the electrolyte, ultimately compromising the electrochemical cycling lifespan. Empirical evidence suggests that the strategic design of the interphase significantly augments the electrochemical reaction kinetics of battery anode materials, concurrently enhancing their structural stability. Nevertheless, a profound understanding of the intricate mechanisms is still lacking, making the establishment of a universal design rule for various anode materials a challenging task. In this review, we categorize the interphases of anode materials into outer and inner interphases based on their physical/chemical environments in batteries. After a comprehensive discussion of the roles and mechanisms of advanced interphases across a range of anode materials, including graphite, alloying-type, and Li metal foil anode materials, we elucidate the principles of outer and inner interphase designs, with an emphasis on enhancing their electrochemical reaction kinetics. Several advanced strategies for the design of electrode structures are also proposed to synergistically enhance the Li⁺ transport processes. Subsequently, we provide typical examples of advanced interphase design, based on the understanding of the proposed interphase design principles for various anodes. Additionally, we offer a review of the future direction of anode interphase design, aiming at the development of high energy density Li-based rechargeable batteries with superior fast-charging capability and long lifespan.