Dual-Functional Lithiophilic/Sulfiphilic Binary-Metal Selenide Quantum Dots Toward High-Performance Li-S Full Batteries.

The commercial viability of lithium-sulfur batteries is still challenged by the notorious lithium polysulfides (LiPSs) shuttle effect on the sulfur cathode and uncontrollable Li dendrites growth on the Li anode. Herein, a bi-service host with Co-Fe binary-metal selenide quantum dots embedded in three-dimensional inverse opal structured nitrogen-doped carbon skeleton (3DIO FCSe-QDs@NC) is elaborately designed for both sulfur cathode and Li metal anode. The highly dispersed FCSe-QDs with superb adsorptive-catalytic properties can effectively immobilize the soluble LiPSs and improve diffusion-conversion kinetics to mitigate the polysulfide-shutting behaviors. Simultaneously, the 3D-ordered porous networks integrated with abundant lithophilic sites can accomplish uniform Li deposition and homogeneous Li-ion flux for suppressing the growth of dendrites. Taking advantage of these merits, the assembled Li-S full batteries with 3DIO FCSe-QDs@NC host exhibit excellent rate performance and stable cycling ability (a low decay rate of 0.014% over 2,000 cycles at 2C). Remarkably, a promising areal capacity of 8.41 mAh cm can be achieved at the sulfur loading up to 8.50 mg cm with an ultra-low electrolyte/sulfur ratio of 4.1 μL mg. This work paves the bi-serve host design from systematic experimental and theoretical analysis, which provides a viable avenue to solve the challenges of both sulfur and Li electrodes for practical Li-S full batteries.