Compression promotes the formation of {110} textures during homoepitaxial deposition of lithium

Abstract

Li metal is an advantageous anode material for high energy-density secondary batteries, while several technical issues, such as instabilities and dendrite formation, hinder its scalable deployment. The electrochemical deposition of Li is an electrocrystallization process where preferred crystallographic growth can be formed. The anisotropy of chemical and physical properties associated with the resulting preferred orientations (i.e., textures) can then be utilized to strengthen the Li metal anode. Understanding texture formation and evolution during homoepitaxial growth is essential for the typical setup of an excess anode inventory. Herein, based on pole figures, inverse pole figures and orientation distribution functions from X-ray diffraction, compression is found to be a critical factor for forming {110} textures during deposition on a Li substrate. Without compression and under a high Li+ transference number environment, a sharp {100}<110> texture is formed in the epitaxial layer up to the high deposition capacity of 20 mAh cm−2, inheriting and intensifying the pre-existing texture of the Li foil substrate. Compression alters the homoepitaxial texture by deformation and dynamic recrystallization to produce a peak-type {110} texture component close to {110}<111>. Due to the low diffusion barrier of Li adatoms and rapid redox process of Li/Li+, the {110} texture is confirmed to be a benefiting factor that enables reduced overpotentials, improved stability and suppressed moss-like dendrites in Li metal anodes. This study adds crystallographic factors to the electrochemo-mechanical correlations of Li metal anodes and provides new opportunities for further optimizations of cell assembly and operation.