ABSTRACT
The slow redox kinetics of lithium-sulfur batteries severely limit their application, and sulfur utilization can be effectively enhanced by designing different cathode sulfur host materials. Herein, we report the hollow porous nanofiber LaNi0.6Co0.4O3 as a bidirectional host material for lithium-sulfur batteries. After Co is substituted into LaNiO3, oxygen vacancies are generated to enhance the material conductivity and enrich the active sites of the material, and the electrochemical reaction rate can be further accelerated by the synergistic catalytic ability of Ni and Co elements in the B-site of the active site of LaNi0.6Co0.4O3. As illustrated by the kinetic test results, LaNi0.6Co0.4O3 effectively accelerated the interconversion of lithium polysulfides, and the nucleation of Li2S and the dissolution rate of Li2S were significantly enhanced, indicating that LaNi0.6Co0.4O3 accelerated the redox kinetics of the lithium-sulfur battery during the charging and discharging process. In the electrochemical performance test, the initial discharge specific capacity of S/LaNi0.6Co0.4O3 was 1140.4 mAh g-1 at 0.1 C, and it was able to release a discharge specific capacity of 584.2 mAh g-1 at a rate of 5 C. It also showed excellent cycling ability in the long cycle test, with a single-cycle capacity degradation rate of only 0.08%. Even under the harsh conditions of high loaded sulfur and low electrolyte dosage, S/LaNi0.6Co0.4O3 still delivers excellent specific capacity and excellent cycling capability. Therefore, this study provides an idea for the future development of bidirectional high-activity electrocatalysts for lithium-sulfur batteries.
