Amorphous CoP nanoparticle composites with nitrogen-doped hollow carbon nanospheres for synergetic anchoring and catalytic conversion of polysulfides in Li-S batteries.

The commercial viability of Li-S batteries was obstructed by short cycle life and poor capability owing to slow redox kinetics and polysulfide shuttle effect. To tackle these challenges, the amorphous CoP anchored on N-doped carbon nanospheres with hollow porous structures (CoP/HCS) has been synthesized as a superior sulfur host via a facial pyrolysis approach. The debilitating effect would be hampered during the cycling processing resulting from two reasons:(1) the powerful chemical anchoring between unsaturated Co and Li-polysulfides, (2) the remarkable adaption of volume variation originating from the hollow porous architectures. The amorphous CoP nanoparticles not only catalyze the transformation of lithium polysulfides as electrocatalyst, but also acquired a high sulfur loading as sulfur host materials. More importantly, the synergistic incorporation of CoP and HCS improved the inherit low conductivity by anchoring on the N-doped carbon hollow, thus leading to excellent performance for Li-S batteries. Benefiting from these advantages, the amorphous CoP/HCS-based sulfur electrodes exhibited outstanding rate performance (685.6 mAh g-1 at 3C), excellent long-cycling stability with a low capacity decay of only 0.03% per cycle over 1000 cycles at 2C, and a high areal capacity of 5.16 mAh cm-2 under high sulfur loading.