Manipulating Li2S2/Li2S mixed discharge products of all-solid-state lithium sulfur batteries for improved cycle life
Jung Tae Kim, Adwitiya Rao, Heng‐Yong Nie, Yang Hu, Weihan Li, Feipeng Zhao, Sixu Deng, Xiaoge Hao, Jiamin Fu, Jing Luo, Hui Duan, Changhong Wang, Chandra Veer Singh, Xueliang Sun
Abstract
Abstract All-solid-state lithium-sulfur batteries offer a compelling opportunity for next-generation energy storage, due to their high theoretical energy density, low cost, and improved safety. However, their widespread adoption is hindered by an inadequate understanding of their discharge products. Using X-ray absorption spectroscopy and time-of-flight secondary ion mass spectrometry, we reveal that the discharge product of all-solid-state lithium-sulfur batteries is not solely composed of Li 2 S, but rather consists of a mixture of Li 2 S and Li 2 S 2 . Employing this insight, we propose an integrated strategy that: (1) manipulates the lower cutoff potential to promote a Li 2 S 2 -dominant discharge product and (2) incorporates a trace amount of solid-state catalyst (LiI) into the S composite electrode. This approach leads to all-solid-state cells with a Li-In alloy negative electrode that deliver a reversible capacity of 979.6 mAh g −1 for 1500 cycles at 2.0 A g −1 at 25 °C. Our findings provide crucial insights into the discharge products of all-solid-state lithium-sulfur batteries and may offer a feasible approach to enhance their overall performance.