A 20 °C operating high capacity solid-state Li-S battery with an engineered carbon support cathode structure

A solid-state lithium-sulfur battery (SSLSB) exhibits much higher theoretical energy density compared with current intercalation electrode-based lithium-ion batteries (LiBs) and possesses excellent safety originated from the less flammable electrolyte. However, a small sulfur loading and limited utilization of active material hamper its practical application. Besides, an elevated temperature is usually required for the operation of SSLSBs. In the present work, a homogeneous nanostructured sulfur-Ketjen black (S@KB) composite cathode was synthesized through an energy-efficient deposition method. A stable and highly ionic conductive composite polymer-ceramic electrolyte (CPE) was employed as the solid-state electrolyte. The SSLSB delivered a pronounced specific capacity of 1108 mA h g⁻¹ and areal capacity of 1.77 mA h cm⁻², and demonstrated stable cycling for 50 cycles. Also, benefiting from fast reaction kinetics, the SSLSB was able to operate at 20 °C and established an excellent rate capability. These results emphasize the morphology control of the cathode plays a critical role in the electrochemical performance of SSLSBs.