The sluggish redox kinetics of polysulfides and difficult oxidation process of Li2S severely hinder practical application of Li–S batteries under high sulfur loading and a low electrolyte dosage. To address these issues, we develop a bifunctional catalyst by manipulation of anion N doping in CoSe2 (N-CoSe2). Theoretical simulation results uncover that an introduced N element into CoSe2 could form a shorter Co–N bond, create a higher charge number of the Co central atom, bring new defect levels, and induce the Co 3d band closer to Fermi level. Further atomic level analysis revealed that N-CoSe2 could form shorter Co–S bonds with sulfur species and simultaneously weaken the S–S bridged bond of Li2S4 and Li–S bond of Li2S, which eventually facilitate the polysulfide conversion reaction in the discharge process and the Li2S oxidation in the charge process. With N-CoSe2 as a bifunctional catalyst, the battery exhibited a high areal capacity of 9.26 mAh g–1 under the low E/S (electrolyte/sulfur) ratio of 4.4 μL mg–1. Understanding the design concept of a bifunctional catalyst with anion doping would provide a new vision for realizing a high-performance Li–S battery.

The development and application of aqueous zinc-ion batteries still face some obstacles, such as dendrite growth and side reactions triggered by active water. Here, we constructed PVA@SR-ZnMoO4 multifunctional coating on...

The slow redox kinetics of polysulfides and the difficulties in decomposition of Li2S during the charge and discharge processes are two serious obstacles to the practical application of lithium-sulfur batteries. Herein, we construct the Fe-Co diatomic catalytic materials supported by hollow carbon spheres to achieve high-efficiency catalysis for the conversion of polysulfides and the decomposition of Li2S simultaneously. The Fe atom center is beneficial to accelerate the discharge reaction process, and the Co atom center is favorable for charging process. Theoretical calculations combined with experiments reveal that this excellent bifunctional catalytic activity originates from the diatomic synergy between Fe and Co atom. As a result, the assembled cells exhibit the high rate performance (the discharge specific capacity achieves 688 mAh g−1 at 5 C) and the excellent cycle stability (the capacity decay rate is 0.018% for 1000 cycles at 1 C).

Controlling exposed crystal facets through crystal facet engineering is an efficient strategy for enhancing the catalytic activity of nanocrystalline catalysts. Herein, the active tin dioxide nano–octahedra enclosed by {332} crystal facets (SnO2 {332}) are synthesized on reduced graphene oxide and demonstrate powerful chemisorption and catalytic ability, accelerating the redox kinetics of sulfur species in lithium–sulfur chemistry. Attributed to abundant unsaturated–coordinated Sn sites on {332} crystal planes, SnO2 {332} has outstanding adsorption and catalytic properties. The material not only adsorbs and converts polysulfides efficiently, but also prominently lowers the decomposition energy barrier of Li2S. The batteries with these high active electrocatalysts exhibit excellent cycling stability with a low capacity attenuation of 0.021% every cycle during 2000 cycles at 2 C. Even with a sulfur loading of 8.12 mg cm−2, the batteries can still cycle stably and maintain a prominent areal capacity of 6.93 mAh cm−2 over 100 cycles. This research confirms that crystal facet engineering is a promising strategy to optimize the performance of catalysts, deepens the understanding of surface structure‐oriented electrocatalysis in Li–S chemistry, while aiding the rational design of advanced sulfur electrodes.

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