Electrocatalytic NiCo2O4 Nanofiber Arrays on Carbon Cloth for Flexible and High-Loading Lithium-Sulfur Batteries.

Lithium-sulfur batteries have ultrahigh theoretical energy densities, which makes them one of the most promising next-generation energy storage systems. However, it is still difficult to achieve large-scale commercialization because of the severe lithium polysulfide (LiPS) shuttle effect and low sulfur loading. Here, we report a flexible lithium-sulfur battery of a high sulfur loading with the assistance of NiCo2O4 nanofiber array grown carbon cloth. The NiCo2O4 nanofibers are ideal electrocatalysts for accelerating LiPS conversion kinetics through strong chemical interactions. Therefore, the composite cathode delivers a high specific capacity of 1280 mAh g-1 at 0.2 C with a sulfur loading of 3.5 mg cm-2, and it can maintain a high specific capacity of 660 mAh g-1 after 200 cycles, showing a good cycle stability. The "layer-by-layer" stacking strategy enables the Li-S battery with a high S loading of ∼9.0 mg cm-2 to deliver a high areal capacity of 8.9 mAh cm-2.