Ni12p5 Nanoparticles Anchored P, N Co-Doped Carbon Nanosheets Modified Separators for Superior Lithium-Sulfur Battery

Abstract

The lithium-sulfur (Li-S) batteries are deemed as a promising candidate for next-generation lithium-based energy storage systems. The shuttle effect due to soluble lithium polysulfides (LiPSs) and sluggish reaction kinetics are considered as the major challenges of electrode design for high-performance lithium-sulfur batteries. In this work, Ni12P5 nanoparticles anchored P, N co-doped carbon nanosheets (Ni12P5/PNC) were synthesized using an in-situ high-temperature phosphorylation method. This material was utilized as an separator in Li-S batteries, which can not only enhance the barrier efficiency by the abundant absorption sites of LiPSs but also reduce the shuttle effect by hindering the migration of LiPSs during cycling. Meanwhile, the high catalytic activity of Ni12P5/PNC effectively promotes the conversion between LiPSs and Li2S2/Li2S. Consequently, the cells with Ni12P5/PNC-modified separators exhibited a high initial capacity of 1300 mAh g-1 at a discharge rate of 0.2 C, and the decay rate is only 0.068% after 600 cycles at a discharge rate of 1 C. Additionally, it is noted that the cells achieve a high area capacity of 3.48 mAh cm-2 at a rate of 0.1 C under an areal loading of 3.22 mg cm-2. The proposed modification method is found to be universal for other transition metal phosphides to modify carbon-based materials.

Keywords: Lithium-sulfur batteries, Molybdenum phosphide, Shuttle effect, Catalytic material.