GO-CoNi alloy promotes internal reaction kinetics of lithium-sulfur batteries to improve long cycle performance at high-rate
Publication Name
Chemical Engineering Journal
Abstract
Mitigating the shuttle reaction and facilitating catalytic conversion within the cell are the primary challenges to the development of high-performance lithium–sulfur batteries. To address these issues, a new type of composite material (GO-CoNi) was synthesized in this study. This material has excellent conductivity and rich active sites for polysulfide adsorption, thus improving the reaction kinetics within the cell. The GO-CoNi-coated separator exhibits an initial discharge capacity of up to 873 mAh/g in a long 2C cycle with a minor decay per cycle (0.04%) after 2000 cycles, and a decay of only 0.146% after 200 cycles in a high-rate 4C cycle. At a high sulfur loading (5.74 mg cm−2), the initial capacity is 962 mAh/g at a current density of 0.1 C, and the system remains stable for 100 cycles. Additionally, the performance of a battery using the GO-CoNi-coated separator is examined at high and low temperatures. At a high temperature of 60 °C, the first-cycle discharge is 1058 mAh/g, and after 100 cycles, the single-cycle decay is 0.417%. A capacity of 871 mAh/g can be realized on the first cycle at a low temperature of 2 °C; after 100 cycles, the single-cycle decays to 0.098%. Furthermore, in-situ Raman experiments provide insights into polysulfide adsorption by GO-CoNi-modified materials and the kinetics of the internal reaction of cells. Additionally, density functional theory confirms that modified materials exhibit strong polysulfide adsorption and promote the catalytic transformation of short-chain polysulfide into Li2S. This study provides a novel approach to promote the practical application of lithium-sulfur batteries, and demonstrates the feasibility of commercial applications through high-rate, high-sulfur loading, high-low temperature experiments.
Open Access Status
This publication is not available as open access
Volume
474
Article Number
145994
Funding Number
2019YFC1906402
Funding Sponsor
National Key Research and Development Program of China