Lei Meng, W. Liu, Chuanzhong Lai, Jingxian Zhang, C. C. Li
Catalytic conversion of the sulfur reduction reaction is regarded as a crucial approach to accelerate the conversion kinetics and inhibit the shuttle effect of soluble lithium polysulfide (LiPS) intermediate products in a high-capacity lithium–sulfur (Li–S) battery system. Exploiting advanced catalysts and designing their microstructure to achieve efficient and durable Li–S batteries is still a challenge. Herein, a composite catalyst Cu 0.145 In 0.855 Ni 3 N/Cu 0.61 Ni 0.39 @C (CINN) with a separate catalysis–deposition site distribution in the dendrite microstructure is synthesized from layered double hydroxide by a simple g-C 3 N 4 vapor modulation method. The LiPS conversion reaction proceeds in a step-by-step manner, with LiPSs adsorbed and catalyzed through Cu 0.145 In 0.855 Ni 3 N antiperovskite domains at the carbon-dendrite tips, which then diffuse and deposit around the Cu 0.61 Ni 0.39 alloy particles embedded in the substrate carbon. This dendritic microstructure maximizes the spatial utilization and durability of catalytic sites. This rational spatial distribution of different functional domains creates a polysulfide nucleation process consisting of top catalysis, diffusion, and substrate deposition. The partial substitution of In atoms by Cu in antiperovskite intensifies the electron-loss ability of In, which can break the Li–S and S–S bonding of long-chain polysulfides, catalyzing the rate-determining step (e.g., Li 2 S 4 to Li 2 S 2 ) of the LiPS conversion reaction. Benefiting from the above-mentioned advantages of the CINN catalyst, the nucleation polarization of the Li–S battery is reduced from 34 to 9 mV, and the activation energy of LiPS conversion into Li 2 S decreases by 48.8 kJ mol –1 . The CINN-modified Li–S batteries exhibit a high discharge capacity (∼1300 mAh g –1 ), outstanding rate performance (500 mAh g –1 at 8 C), and great durability (641 mAh g –1 at 1 C after 400 cycles).