Enabling High-Areal-Capacity Lithium-Sulfur Batteries: Designing Anisotropic and Low-Tortuosity Porous Architectures

Lithium-sulfur (Li-S) batteries have attracted much attention due to their high theoretical energy density in comparison to conventional state-of-the-art lithium-ion batteries. However, low sulfur mass loading in the cathode results in low areal capacity and impedes the practical use of Li-S cells. Inspired by wood, a cathode architecture with natural, three-dimensionally (3D) aligned microchannels filled with reduced graphene oxide (RGO) were developed as an ideal structure for high sulfur mass loading. Compared with other carbon materials, the 3D porous carbon matrix has several advantages including low tortuosity, high electrical conductivity, and good structural stability, which make it an excellent 3D lightweight current collector. The Li-S battery assembled with the wood-based sulfur electrode can deliver a high areal capacity of 15.2 mAh cm^-2 with a sulfur mass loading of 21.3 mg cm^-2. This work provides a facile but effective strategy to develop 3D porous electrodes for Li-S batteries, which can also be applied to other cathode materials to achieve a high areal capacity with uncompromised rate and cycling performance.