Multi-functional nanowall arrays with unrestricted Li+ transport channels and an integrated conductive network for high-areal-capacity Li–S batteries

Abstract

The rational design of cathode hosts with superior polysulfide (PS) confinement properties, excellent Li⁺/e⁻ transport and improved cyclability is of the utmost importance for high-areal-capacity lithium–sulfur (Li–S) batteries. Herein, multi-functional nanowall arrays (MNWAs) combining the aforementioned properties are fabricated to improve the electrochemical performance of Li–S batteries with high areal sulfur loadings. The integrated conductive networks and top-down vertically aligned Li⁺ transport channels are beneficial to Li⁺/e⁻ transport, resulting in high rate performance with a discharge capacity of 620 mA h g⁻¹ at a high current density of 9.6 mA cm⁻² for 4 mg cm⁻² sulfur-loaded S/MNWA electrodes. Additionally, the strong PS shuttling suppression via the synergetic effects of physical confinement and chemical adsorption leads to Li–S batteries with a sulfur loading of 10 mg cm⁻² capable of delivering a high areal capacity of 12.4 mA h cm⁻² with a high capacity retention of nearly 85% for over 100 cycles. What's more, the Li–S batteries assembled with 4 mg cm⁻² sulfur-loaded S/MNWA electrodes show an ultra-low capacity decay of 0.07% per cycle over 400 cycles at 3.2 mA cm⁻².