Spatial structure design of interlayer for advanced lithium–sulfur batteries

Abstract

The practical application of lithium-sulfur (Li–S) batteries has been hindered by the lithium polysulfide shuttle effect. An effective way to solve this problem is to utilize interlayer engineering to confine polysulfides and promote their catalytic conversion. From a spatial perspective, we designed a carbon nanofiber conductive layer (CNF, without Sn content, labeled as 0) and two Sn-doped carbon nanofiber catalytic layers (SCNF, with 10 wt% and 20 wt% Sn content, labeled as 1 and 2, respectively) with different contents of catalyst content, and verified an efficient interlayer structure by adjusting the order of preferential contact between the conductive layer and the catalytic layer with the sulfur cathode to form a hierarchical system for the inhibition and conversion of lithium polysulfide. Electrochemical measurements show that different spatial configurations have significant discrepancies on the electrochemical performance of Li–S batteries. Thus, the space configuration of 210 enables the Li–S battery to provide a specific capacity of up to 1088 mAh g⁻¹ after 100 cycles at 0.2C. Even under the harsh conditions of high sulfur loading (5.6 mg cm⁻²) and lean electrolyte (E/S = 10 μL mg⁻¹), the Li–S battery was able to cycle stably for 94 cycles at 0.2C with 87 % capacity retention. This study provides a novel spatial strategy for advancing the spatial design of high-performance Li–S batteries.