Long‐Life and High‐Loading All‐Solid‐State Li–S Batteries Enabled by Acetylene Black with Dispersed Co‐N4 as Single Atom Catalyst

All-solid-state Li–S batteries (ASSLSBs) have exhibited great promise as next-generation energy storage systems due to the elimination of the shuttle effect and flammability. However, the low reactivity of sulfur and poor solid–solid contact in the composite cathode result in limited electrochemical performances. Here, a Co-N4-decorated carbon composite is prepared by direct ball milling and serves as a sulfur host for ASSLSBs. The uniform distribution of Co-N4 can effectively accelerate the redox conversion of sulfur and inhibit the agglomeration of sulfur particles during cycling through strong chemical affinity. Benefiting from these merits, the sulfur cathode with a sulfur content of 40% and a sulfur loading of 1.5 mg cm−2 in ASSLSBs exhibits high reversible capacity (1439 mAh g−1 at 0.1 C) and superior long-term cyclic performance (capacity fade rate of 0.025% per cycle for 1000 cycles at 0.5 C). Even under a sulfur loading up to 4.5 mg cm−2, the areal capacity can reach 5.13 mAh cm−2 at 60 °C and maintain stable cycling over 300 cycles at 0.3 C. This work offers a promising strategy for enhancing the electrochemical performance of ASSLSBs.