Multilayer Approach for Advanced Hybrid Lithium Battery

Conventional intercalated rechargeable batteries have shown their capacity limit, and the development of an alternative battery system with higher capacity is strongly needed for sustainable electrical vehicles and hand-held devices. Herein, we introduce a feasible and scalable multilayer approach to fabricate a promising hybrid lithium battery with superior capacity and multivoltage plateaus. A sulfur-rich electrode (90 wt % S) is covered by a dual layer of graphite/Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub>, where the active materials S and Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub> can both take part in redox reactions and thus deliver a high capacity of 572 mAh g<sub>cathode</sub><sup>–1</sup> (<i>vs</i> the total mass of electrode) or 1866 mAh g<sub>s</sub><sup>–1</sup> (<i>vs</i> the mass of sulfur) at 0.1C (with the definition of 1C = 1675 mA g<sub>s</sub><sup>–1</sup>). The battery shows unique voltage platforms at 2.35 and 2.1 V, contributed from S, and 1.55 V from Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub>. A high rate capability of 566 mAh g<sub>cathode</sub><sup>–1</sup> at 0.25C and 376 mAh g<sub>cathode</sub><sup>–1</sup> at 1C with durable cycle ability over 100 cycles can be achieved. Operando Raman and electron microscope analysis confirm that the graphite/Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub> layer slows the dissolution/migration of polysulfides, thereby giving rise to a higher sulfur utilization and a slower capacity decay. This advanced hybrid battery with a multilayer concept for marrying different voltage plateaus from various electrode materials opens a way of providing tunable capacity and multiple voltage platforms for energy device applications.