A multifunctional self-supporting LLTO/C interlayer for high-performance lithium-sulfur batteries.

Abstract

Lithium-sulfur (Li-S) batteries are recognized as an encouraging alternative for future power storage technologies. However, their practical application is hindered by several significant challenges, including slow redox kinetics, the shuttle effect, and the formation of lithium dendrites. Here a binder-free, self-supporting multifunctional interlayer composed of lithium lanthanum titanate (LLTO) with amorphous carbon nanofiber matrices for Li-S batteries has been constructed. This multifunctional interlayer has been designed to facilitate the redox kinetics of lithium polysulfides (LiPSs), promote the nucleation of lithium sulfide (Li2S), and hinder the formation of lithium dendrites. The electrocatalytic properties of the interlayer were subjected to systematic evaluation through electrochemical testing, and the lithium deposition was assessed by examining the surface evolution of lithium metal in symmetric cells. The LLTO carbon matrix interlayer sustained a high specific capacity of 703.3 mA h g-1 after 200 cycles at 0.1C, with a sulfur loading of 5.5 mg cm-2. Furthermore, it demonstrated a high capacity of 905.9 mA h g-1 with a decay rate of 0.069% per cycle over 1000 cycles at a current density of 5C with a sulfur loading of 1 mg cm-2. This investigation highlights the potential of LLTO carbon composite materials as multifunctional interlayers, which could facilitate the optimization of advanced Li-S batteries.