DNA-Guided Li2S Nanostructure Deposition for High-Sulfur-Loaded Li–S Batteries

Abstract

The low areal capacity caused by low sulfur loading (<2.0 mg cm–2) and the poor sulfur utilization due to the insulating Li2S layer covering the cathode always limit the practical applications of lithium–sulfur batteries (Li–S batteries). Deoxyribonucleic acid (DNA)-controlled nucleation and growth of Li2S in the Li–S system were first studied in this work. The negatively charged sugar-phosphate backbone of DNA could attract Li+ ions and allow crystalline Li2S to grow along the DNA chains. The electrodeposition of Li2S with a unique three-dimensional nanostructure during the polysulfide conversion and deposition process was realized, which can not only boost electron and ion transport but also expose and retain more active sites in the cathode. A Li–S battery with ultrahigh sulfur loading of 10 mg cm–2 and a low electrolyte/sulfur ratio of 6.08 delivered a high areal capacity of 8.1 mA h cm–2, which is more than 2 times that of commercial Li-ion batteries, demonstrating a great enhancement of the Li–S battery compared to other studies. Therefore, this study provides an effective strategy of DNA-guided 3D Li2S deposition for achieving high-sulfur-loading Li–S batteries.