Multifunctional Catalytic Hierarchical Interfaces of Ni₁₂P₅-Ni₂P Porous Nanosheets Enabled Both Sulfides Reaction Promotion and Li-Dendrite Suppression for High-Performance Li-S Full Batteries

The development of lithium-sulfur (Li-S) batteries is very promising and yet faces the issues of hindered polysulfides conversion and Li dendrite growth. Different from using different materials strategies to overcome these two types of problems, here multifunctional catalytic hierarchical interfaces of Ni12P5-Ni2P porous nanosheets formed by Ni2P partially in situ converted from Ni12P5 are proposed. The unique electronic structure in the interface endows Ni12P5-Ni2P effective electrocatalysis effect toward both sulfides' reduction and oxidation through reducing Gibbs free energies, indicating a bidirectional conversion acceleration. Importantly, Ni12P5-Ni2P porous nanosheets with hierarchical interfaces also reduced the Li nucleation energy barrier, and a dendrite-free Li deposition is realized during the overall Li deposition and stripping steps. To this end, Ni12P5-Ni2P decorated carbon nanotube/S cathode showing a high capacity of over 1500 mAh g(-1), and a high rate capability of 8 C. Moreover, the coin full cell delivered a high capacity of 1345 mAh g(-1) at 0.2 C and the pouch full cell delivered a high capacity of 1114 mAh g(-1) at 0.2 C with high electrochemical stability during 180 degrees bending. This work inspires the exploration of hierarchical structures of 2D materials with catalytically active interfaces to improve the electrochemistry of Li-S full battery.