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Though lithium‐sulfur (Li−S) batteries possess extremely high theoretical energy density (2600 Wh kg−1), its practical application is significantly hindered due to the shuttle effect of lithium polysulfides and poor electronic conductivity of cycling products. For this case, developing new type of cathodes with high electronic conductivity and appropriate adsorption energy is an important strategy to improve the Li−S battery performance. Herein, by using first‐principle calculations, we systematically investigate the two‐dimensional transition metal organic framework compounds TM‐BHT (TM=transition metal, BHT=benzenehexathiol) as the possible cathode candidates for Li−S batteries. Among the various TM‐BHT system, Co/Ni/Cu‐BHT are considered to be potential cathode materials for the excellent electronic conductivity, moderate adsorption energy and structural stability. In addition, it is found that the Co/Ni/Cu‐BHT can not only catalyze the decomposition reactions of S8/Li2Sn, but also synergistically discharge with sulfur materials. This work demonstrates an effective design pathway and provides solutions for developing high‐performance Li−S batteries. [ABSTRACT FROM AUTHOR]

2D conductive metal–organic frameworks (2D c‐MOFs) have emerged as novel cathode materials in the development of rechargeable aqueous zinc‐ion batteries (ZIBs) because of its integrated multiple redox‐active moieties. However, the redox of the metal nodes usually leads to the collapse of the c‐MOF structure during Zn2+ insertion/extraction process, thereby curtailing its cycling lifespan. Herein, a triphenylene‐catecholate‐based 2D c‐MOF (Zn‐HHTP) is fabricated by chelating the inactive Zn nodes, endowing the structural stability during charge and discharge processes only through ligand redox. The 1D open channel of Zn‐HHTP facilitates rapid insertion and extraction of zinc ions, thus enabling stable working of ZIBs at high rates. Impressively, Zn‐HHTP as cathode in ZIBs exhibits an ultra‐long cycling stability with capacity retention of 86.6% after 4000 cycles at the current density of 4 A g−1, exceeding the other MOF‐based cathodes ever reported. Density functional theory (DFT) calculations combined with ex situ X‐ray photo‐electron spectroscopy (XPS) further elucidate the redox mechanism between catechol and benzene ring of HHTP during the successive insertion/extraction of Zn2+, due to their comparatively negative electrostatic potentials. This work provides a new strategy to prolong the cycling capability of ZIBs by utilizing the highly active non‐metallic redox moieties in 2D c‐MOFs. [ABSTRACT FROM AUTHOR]

Based on density functional theory, transition metal-doped α-borophene was studied as potential electrocatalyst for the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). It was found that Ni- and Pd-doped α-borophene sheets display advantageous catalytic activity toward OER, while Fe-, Co-, Cu-, Ru-, Rh-, Ag-, and Pt-doped α-borophene sheets can exhibit high catalytic activity toward HER. The most important aspect is that α-borophene can suppress the aggregation of Fe, Co, Ni, Cu, and Pd atoms toward clusters formation. Through rational selection, bimetal-doped α-borophene can exhibit excellent bifunctional catalysis toward OER and HER. Unlabelled Image • Ni- and Pd-doped α-borophene sheets display high catalytic activity toward OER. • Fe-, Co-, Cu-, Ag-, and Pt-doped α-borophene exhibit high activity toward HER. • α-borophene suppresses the aggregation of Fe, Co, Ni, Cu, and Pd atoms. • Bimetal-doped α-borophene exhibits bifunctional catalysis toward OER and HER. [ABSTRACT FROM AUTHOR]