Nanofluidic-enhanced high-mass-loading electrodes for energy-dense and high-rate lithium-sulfur batteries

Abstract

High-mass-loading sulfur cathodes with high areal capacity are critical for developing energy-dense lithium-sulfur (Li-S) batteries. However, facilitating efficient Li+ ion and electron transport in high-mass-loading sulfur electrodes remains a great challenge due to the extended pathways and inferior ion-electron transfer, especially at a high charge/discharge rate. To address the issue, we develop an ion-gated coating layer inspired by the nanofluidic effects in organisms (IGCL-NFE), which enhances the Li+ diffusion coefficient (D) and transference number (µ+) to enable ultrafast and selective Li+ transport in thick sulfur electrodes. The IGCL-NFE exhibits a characteristic biomimetic nanofluidic ion transport behavior, yielding a high µ+ (~2.1 times higher than that in the bulk solution) and a high D (~1012 times higher than that in the bulk solution) at a low Li salt concentration of 10-6 mol L-1. With selective and fast Li+ conduction, coupled with the high electrical conductivity of the IGCL-NFE, the IGCL-NFE-enhanced sulfur cathode demonstrates exceptional rate performance (757.8 mAh g-¹ after 300 cycles) at a high rate of 10.0 C. As a proof of concept, Li-S batteries utilizing the dry electrode with an ultrahigh sulfur loading of 18.7 mg cm-2 achieve an impressive energy density of 430.6 Wh kg-1. Furthermore, the Li-S full cell exhibits stable cycling performance over 100 cycles, retaining a high capacity of 1313.9 mAh g-¹ even at -20 °C. The nature-inspired, nanofluidic-enhanced electrode design presents a promising strategy for developing ultrahigh-mass-loading and high-rate Li-S batteries.