Low Tortuosity and Reinforced Concrete Type Ultra-Thick Electrode for Practical Lithium–Sulfur Batteries

High-energy density and ultra-long cycling lifespan are of great significance in pursuit of practical lithium–sulfur (Li-S) batteries, in which the construction of ultrathick, high-areal-capacity, and stable-cycling sulfur cathodes remains challenging. Here, a unique layered reinforced concrete structure (LRCS) is reported by integrating an ice-template method with incorporating carbon fibers in the thick electrodes for Li-S batteries. The LRCS enables aligned through-channel structure and intertwined conductive network, which lead to both fast kinetics of ions/electrons transport and strengthened electrode integrity to tolerate the volume change during cycling and the dimensional deformation under a high compaction density. Benefiting from the unique structure, the ultra-thick Se 0.05 S 0.95 @ pPAN cathode (20.2 mg cm −2 ) delivers a high capacity of 10 mAh cm −2 and excellent capacity retention of 80.8% over 140 cycles at a low electrolyte-to-sulfur ratio of 2 and a negative-to-positive capacity ratio of 2.7, corresponding to a calculated energy density of 390 Wh kg −1 . This investigation not only provides guidance for the design of thick sulfur electrodes but also paves the way for the development of practical Li-S batteries.