Improved interfacial electronic contacts powering high sulfur utilization in all-solid-state lithium–sulfur batteries

All-solid-state lithium–sulfur batteries (ASSLSBs) afford a novel avenue for next-generation high energy density lithium–sulfur batteries due to the alleviated potential safety hazards. However, ASSLSBs suffer from high interfacial impedance and poor kinetics of electrochemical reactions. Herein, we probed the interfacial electron transfer between active sulfur and conductive carbon in a working cell. The co-axial carbon nanotube@sulfur composite with more robust electron contacts enables fast electron transportation and reduced interfacial charge transfer impedance, leading to a high sulfur utilization and excellent electrochemical performance. An initial discharge capacity of 1138.7 mAh g⁻¹ at 0.21 mA cm⁻² (0.1C) with a capacity retention of 87.7% after 200 cycles is achieved at a sulfur loading of 1.3 mg cm⁻². Moreover, the cathode with superior and uniform electronic contacts delivers better rate capability and a higher discharge specific capacity at a high sulfur loading ranging from 3.8 to 5.9 mg cm⁻². This work verifies the significance of 3D interconnected electronic pathways in the sulfur cathode for high performance ASSLSBs.