ZIF-Derived Carbon Nanoframes as a Polysulfide Anchor and Conversion Mediator for High-Performance Lithium-Sulfur Cells.

Improving the redox kinetics of sulfur species, while suppressing the "shuttle effects" to achieve stable cycling under high sulfur loading is an inevitable problem for lithium-sulfur (Li-S) cells to commercialization. Herein, the three-dimensional Zn, Co, and N codoped carbon nanoframe (3DZCN-C) was successfully synthesized by calcining precursor which protected by mesoporous SiO and was used as cathode host for the first time to improve the performance of Li-S cells. Combining the merits of strong lithium polysulfides (LiPSs) anchoring and accelerating the conversion kinetics of sulfur species, 3DZCN-C effectively inhibit the shuttling of LiPSs and achieves excellent cyclability with capacity fading rate of 0.03% per cycle over 1000 cycles. Furthermore, the Li-S pouch cell has been assembled and has been shown to operate reliably with high energy density (>300 Wh kg) even under a high sulfur loading of 10 mg cm. This work provides a simple and effective way for the promotion and commercial application of Li-S cells.