Urchin-shaped NiCo 2 Se 4 (u-NCSe) nanostructures as efficient sulfur hosts are synthesized to overcome the limitations of lithium-sulfur batteries (LSBs). u-NCSe provides a beneficial hollow structure to relieve volumetric expansion, a superior electrical conductivity to improve electron transfer, a high polarity to promote absorption of lithium polysulfides (LiPS), and outstanding electrocatalytic activity to accelerate LiPS conversion kinetics. Owing to these excellent qualities as cathode for LSBs, S@u-NCSe delivers outstanding initial capacities up to 1403 mAh g −1 at 0.1 C and retains 626 mAh g −1 at 5 C with exceptional rate performance. More significantly, a very low capacity decay rate of only 0.016% per cycle is obtained after 2000 cycles at 3 C. Even at high sulfur loading (3.2 mg cm −2 ), a reversible capacity of 557 mAh g −1 is delivered after 600 cycles at 1 C. Density functional theory calculations further confirm the strong interaction between NCSe and LiPS, and cytotoxicity measurements prove the biocompatibility of NCSe. This work not only demonstrates that transition metal selenides can be promising candidates as sulfur host materials, but also provides a strategy for the rational design and the development of LSBs with long-life and high-rate electrochemical performance.

A methanol economy will be favored by the availability of low‐cost catalysts able to selectively oxidize methanol to formate. This selective oxidation would allow extraction of the largest part of the fuel energy while concurrently producing a chemical with even higher commercial value than the fuel itself. Herein, we present a highly active methanol electrooxidation catalyst based on abundant elements and with an optimized structure to simultaneously maximize interaction with the electrolyte and mobility of charge carriers. In situ infrared spectroscopy combined with nuclear magnetic resonance spectroscopy showed that branched nickel carbide particles are the first catalyst determined to have nearly 100 % electrochemical conversion of methanol to formate without generating detectable CO2 as a byproduct. Electrochemical kinetics analysis revealed the optimized reaction conditions and the electrode delivered excellent activities. This work provides a straightforward and cost‐efficient way for the conversion of organic small molecules and the first direct evidence of a selective formate reaction pathway.

Superlattices are rising stars on the horizon of energy storage and conversion, bringing new functionalities; however, their complex synthesis limits their large‐scale production and application. Herein, a simple solution‐based method is reported to produce organic–inorganic superlattices and demonstrate that the pyrolysis of the organic compound enables tuning their interlayer space. This strategy is exemplified here by combining polyvinyl pyrrolidone (PVP) with WSe2 within PVP/WSe2 superlattices. The annealing of such heterostructures results in N‐doped graphene/WSe2 (NG/WSe2) superlattices with a continuously adjustable interlayer space in the range from 10.4 to 21 Å. Such NG/WSe2 superlattices show a metallic electronic character with outstanding electrical conductivities. Both experimental results and theoretical calculations further demonstrate that these superlattices are excellent sulfur hosts at the cathode of lithium–sulfur batteries (LSB), being able to effectively reduce the lithium polysulfide shuttle effect by dual‐adsorption sites and accelerating the sluggish Li–S reaction kinetics. Consequently, S@NG/WSe2 electrodes enable LSBs characterized by high sulfur usages, superior rate performance, and outstanding cycling stability, even at high sulfur loadings, lean electrolyte conditions, and at the pouch cell level. Overall, this work not only establishes a cost‐effective strategy to produce artificial superlattice materials but also pioneers their application in the field of LSBs.

The shuttling of soluble lithium polysulfides (LiPS) and the sluggish Li–S conversion kinetics are two main barriers toward the practical application of lithium–sulfur batteries (LSBs). Herein, we propose the addition of copper selenide nanoparticles at the cathode to trap LiPS and accelerate the Li–S reaction kinetics. Using both computational and experimental results, we demonstrate the crystal phase and concentration of copper vacancies to control the electronic structure of the copper selenide, its affinity toward LiPS chemisorption, and its electrical conductivity. The adjustment of the defect density also allows for tuning the electrochemically active sites for the catalytic conversion of polysulfide. The optimized S/Cu1.8Se cathode efficiently promotes and stabilizes the sulfur electrochemistry, thus improving significantly the LSB performance, including an outstanding cyclability over 1000 cycles at 3 C with a capacity fading rate of just 0.029% per cycle, a superb rate capability up to 5 C, and a high areal capacity of 6.07 mAh cm–2 under high sulfur loading. Overall, the present work proposes a crystal phase and defect engineering strategy toward fast and durable sulfur electrochemistry, demonstrating great potential in developing practical LSBs.