Electrode Design with Integration of High Tortuosity and Sulfur-Philicity for High-Performance Lithium-Sulfur Battery

The high-energy-density Li-S battery is limited by the diffusion loss of active polysulfide (PS) in cathode (degraded cycling capacity/stability) and dendrite growth in Li anode (safety concern). Here, we develop an integrated high-tortuosity and sulfur-philicity design for thick sulfur cathode. The high tortuosity from horizontal alignment of reduced graphene oxide (rGO) sheets, which enhances the physical complexity of mass transport inside the electrode, can localize the soluble PS within the electrode instead of outward diffusion loss. The high sulfur-philicity (from oxygen groups in rGO) favors bonding PS with electrode matrix surface to mitigate its diffusion. With this integrated design, outstanding cathode areal capacities of 21 mAh cm⁻² and 98.1% retention after 160 cycles are achieved. In addition, the same rGO host suppresses the Li dendrite growth in anode with 278% prolonged cycle life. This high-tortuosity and sulfur-philicity design shows a new principle for future Li-S batteries.