Improved performance of CoS<inf>2</inf> nanoparticles encapsulated in carbon micro-polyhedron for propelling redox reaction of polysulfide

• Key Words:Lithium compounds;Carbon - Cathodes - Electrocatalysts - Geometry - Nanocatalysts - Nanoparticles - Polysulfides - Porous materials - Reaction kinetics - Redox reactions - Secondary batteries - Synthesis (chemical)
• Abstract:Recently, a strategy of catalysis is reported to accelerate the chemical kinetics of polysulfide conversion and fundamentally solve shuttle effect of polysulfide. Herein, CoS<inf>2</inf> nanoparticles catalyst embedded in porous carbon polyhedron (NC–CoS<inf>2</inf>) are prepared through in situ method. The CoS<inf>2</inf> nanoparticles keep tight connection with carbon, which enable them effectively get electrons through carbon and catalyze the conversion of polysulfide. The porous carbon polyhedron shows high absorption ability to polysulfide and can immobilize polysulfide around CoS<inf>2</inf> nanoparticles, which improve the utilization of catalysis sites. With the synergistic effect of porous structure and CoS<inf>2</inf> nanoparticles, the Li–S batteries with NC-CoS<inf>2</inf> cathode can deliver as high as 1600 and 1150 mAh g⁻¹ at current density of 0.1 and 0.5C, respectively. After cycling 150 times at 0.1C, a capacity of 1050 mAh g⁻¹ is retained. Additionally, the NC-CoS<inf>2</inf> cathode shows high initial discharge capacity of 920 mAh g⁻¹ at 2 C, and about 835 mAh g⁻¹ has been reserved after 100 cycles. The results indicate that the CoS<inf>2</inf> nanoparticles play a crucial role in improving the performance of batteries owing to their propelling redox reaction of polysulfide.<br/> © 2019
• Volume:324
• Translation or Not:no