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

Practical applications of Li-S batteries are hindered by the dissolution/diffusion loss of sulfur-related active materials in cathode and dendrite growth in Li metal anode. Here we present an integrated sulfur cathode design on tortuosity and sulfur-binding affinity parameters for mitigating diffusion loss of sulfur-based active materials. The high sulfur-philicity property (from oxygen functional groups, 16% in concentration) in reduced graphene oxide (rGO) host favors bonding with sulfur species to mitigate their diffusion/dissolution loss, while the high tortuosity (13.24, from horizontal arrangement of rGO sheets) can localize the soluble active materials within the host rather than outward diffusion loss with subsequent uneven redeposition. With this integrated concept, we achieved ultrahigh cathode areal capacities of 21 mAh cm−2 with 98.1% retention after 160 cycles, surpassing those electrodes with lower tortuosity and sulfur-philicity. In addition, same rGO host suppresses dendrite growth in Li anode, enabling 278% prolonged cycle life in the full cell. [Display omitted] •High tortuosity suppresses diffusion loss of polysulfide from sulfur cathode•High sulfur-philicity favors bonding sulfur-based materials within the electrode•Same graphene host suppresses Li dendrite growth in anode to prolong cycle life•Ultrahigh loading and ultrastable cycling under high-energy-density parameters 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. The Li-S battery is limited by diffusion loss of soluble polysulfide activ