A Nickel-decorated porous graphitized carbon/sulfur cathode enabling excellent cycling stability of all-solid-state lithium-sulfur batteries

Abstract

• A high electrical conductivity of Nickel-decorated porous graphitized carbon (Ni-PGC) host materials are prepared by a simple and effective calcination. • Ni-PGC-sulfur cathode realizes the fast redox kinetics of all-solid-state lithium-sulfur batteries. • Applying Ni-PGC-S material to all-solid-state Li-S battery can significantly improve the utilization of active materials. All-solid-state lithium-sulfur batteries (ASSLSBs) with high theoretical specific capacity and low cost are considered a promising electrochemical energy storage system. However, it suffers from large polarization, low sulfur utilization, and severe capacity decay, owing to the sluggish solid-solid reactions between sulfur and its discharging products (such as lithium sulfide, etc.). Herein, a Nickel-decorated porous graphitized carbon (Ni-PGC) is prepared using a one-step calcination method for the sulfur host in ASSLSBs with PEO-based solid electrolytes. The high specific surface area (638.2 m 2 g -1 ) of porous carbon structure with sufficient pore volume (0.69 cm 3 g -1 ) could uniformly disperse the active material (Sulfur). The metallic Nickel nanoparticles embedding in the porous network could significantly improve the electronic conductivity of composite cathode in ASSLSBs. As a result, the higher electrical conductivity of 8.22 S cm -1 is achieved from the Ni-PGC-S cathode, compared to 0.33 S cm -1 for the amorphous carbon-sulfur cathode. Furthermore, Li + diffusion coefficients (4.19×10 -11 cm 2 s -1 at the cathodic peak of 2.40 V, 7.54×10 -11 cm 2 s -1 at the cathodic peak of 2.05 V, and 2.69×10 -10 cm 2 s -1 at the anodic peak of 2.35 V) of the Ni-PGC-S cathode at 60 o C, are 11.11 times, 3.17 times and 2.17 times of the amorphous carbon-sulfur cathode without Ni doping. Therefore, the all-solid-state lithium-sulfur batteries assembled with the Ni-PGC-S cathode exhibit an extraordinary initial discharge capacity of 1311.3 mAh g -1 and a low cycling degradation (0.30 % per cycle) at 60 o C and 0.1 C. Even at 1 C, the battery delivers 375.8 mAh g -1 after 300 cycles.