Small intestinal structure Ni2P-CNTs@ NHCF nanoreactor accelerating sulfur conversion kinetics for high performance lithium-sulfur batteries
Abstract
It is extremely desirable to develop efficient sulfur reduction reaction (SRR) electrocatalysts for lithium-sulfur (Li–S) batteries. In this work, a small intestinal structure sulfur electrocatalyst, viz. Ni2P-CNTs@NHCF nanoreactor, is designed by a facile coaxial electrostatic spinning strategy. Experimental results and theoretical calculations indicate that the synergetic effect of Ni–S and Li–P dual chemical bonds between Ni2P and lithium polysulfides (LiPSs) optimizes the chemisorption energy of LiPSs and reduces reaction energy barriers from liquid LiPSs to solid Li2S, thus achieving the successive immobilization-diffusion-conversion process of sulfur species. As a result, the cell modified with Ni2P-CNTs@NHCF catalyst exhibits the excellent reversible capacities and cyclic stability. With the high sulfur loading of 8.13?mg?cm?2 and low electrolyte/sulfur ratio of 6?μL?mg?1, it displays a significant initial areal capacity of 13.4?mAh?cm?2 and remains 7.1?mAh?cm?2 after 80 cycles at 0.1 C. This work offers an effective strategy on rational design of efficient electrocatalysts, and provides considerable insights into the mechanical comprehension of SRR.