Novel Lithiophilic Silver Selenide Nanocrystals within Porous Carbon Microsphere: Tailoring Pore Structures for Enhanced Lithium Metal Battery Anodes

Abstract

To enable the practical use of a lithium metal anode, the rational design of three-dimensional (3D) host materials is considered as a promising approach to mitigate lithium dendrite formation and accommodate substantial volume fluctuations. Herein, we first design a 3D conductive host material comprised of Ag₂Se nanocrystals encapsulated within closed pore structured porous carbon microspheres. The homogeneous distribution of the AgLi alloy and Li₂Se phases, generated through the consecutive conversion and alloying reaction of the Ag₂Se phase, enables the developed host materials to exhibit rapid lithium deposition kinetics. Additionally, the inner void structures with encapsulated lithiophilic nanocrystals promote primary deposition within the carbon framework without dendrite growth. Consequently, optimized pore structure as well as position of lithiophilic nanocrystals in carbon microsphere are rationally tailored for stable plating/stripping behaviors of lithium with high Coulombic efficiency and stable voltage profiles. Paired with the LiNi_0.8Co_0.1Mn_0.1O₂ cathode, the assembled full cell demonstrates outstanding cycling stability and impressive high-rate performance, highlighting its potential for practical applications. Moreover, to explore how different pore structures influence the stability of the Li metal host, Ag₂Se@C hosts with various pore structures (including open pore structures and densely structured configurations without inner voids) are also fabricated and compared with the developed host material.

Keywords: lithiophilic materials; lithium metal host; porous structure; silver selenide; spray pyrolysis.