Direct-Contact Prelithiation of Si-C Anode Study as a Function of Time, Pressure, Temperature, and the Cell Ideal Time

Abstract

Direct-contact prelithiation (pl) is a facile, practical, and scalable method to overcome the first-cycle loss and large volume expansion issues for silicon anode (with 30 wt % si loading) material, and a detailed study is absent. Here, an understanding of direct-contact pl as a function of the pl time, and the effects of externally applied pressure (weight), microstructure, and operating temperature have been studied. The impact of pl on the si-c electrode surfaces has been analyzed by electrochemical techniques and different microstructural analyses. The solid electrolyte interface (sei) layer thickness increases with the increase in pl time and decreases after 2 min of pl time. The ideal pl time was found to be between 15 (pl-15) and 30 (pl-30) min with 83.5 and 97.3% initial coulombic efficiency (ice), respectively, for 20 g of externally applied weight. The pl-15 and pl-30 cells showed better cyclic stability than pl-0 (without prelithiation), with more than 90% capacity retention after 500 cycles at 1 a g-1 current density. The discharge capacities for pl-15 and pl-30 have been observed as highest at 45 °c operating temperature with limited cyclability. We propose here a synchronization strategy in prelithiation time, pressure, and temperature to achieve excellent cell performance. © 2022 american chemical society.