Bimetallic nitride modified separator constructs internal electric field for high-performance lithium-sulfur battery

Abstract

Due to higher theoretical capacity and lower cost, the lithium-sulfur battery gradually replaces the traditional lithium-ion battery. Unfortunately, the shuttle effect of lithium-sulfur batteries is an important factor that hinders their marketization inputs. In this article, we propose an in-situ extrinsic metal etching strategy to activate inert single-metal nitrides through doping methods. The construction of the functional layer on the diaphragm results in an internal electric field directed to the negative electrode between the diaphragm and the negative electrode. The construction of the internal electric field is benefit for the moving of the anions and cations, thereby reducing the dissolution of the polysulfides. Moreover, it is found that the initial capacity reaches 1421 mAh g−1 and the utilization of sulfur reaches 84.83% at 0.1C. The initial capacity is 1280.8 mAh g−1, and there is 466.4 mAh g−1 specific capacity remaining after 1400 cycles and the decay rate is 0.045% at the rate of 1C. Even at the high rate of 5C, the initial capacity is 1097.2 mAh g−1 and the specific capacity of 379.4 mAh g−1 remains after 800 cycles.