Ni(OH)2 nanosheet, acting as a potential active material for supercapacitors, commonly suffers from sluggish reaction kinetics and low intrinsic conductivity, which results in suboptimal energy density and long cycle life. Herein, a convenient electrochemical halogen functionalization strategy is applied for the preparation of mono/bihalogen engineered Ni(OH)2 electrode materials. The theoretical calculations and experimental results found that thanks to the extraordinarily high electronegativity, optimal reversibility, electronic conductivity, and reaction kinetics could be achieved through F functionalization . However, benefiting from the largest ionic radius, INi(OH)2 contributes the best specific capacity and morphology transformation, which is a new finding that distinguishes it from previous reports in the literature. The exploration of the interaction effect of halogens (F, INi(OH)2, F, BrNi(OH)2, and Cl, INi(OH)2) manifests that F, INi(OH)2 delivers a higher specific capacity of 200.6 mAh g−1 and an excellent rate capability of 58.2% due to the weaker electrostatic repulsion, abundant defect structure, and large layer spacing. Moreover, the F, INi(OH)2//FeOOH@NrGO device achieves a high energy density of 97.4 Wh kg−1 and an extremely high power density of 32426.7 W kg−1, as well as good cycling stability. This work develops a pioneering tactic for designing energy storage materials to meet various demands.

Structurally optimized transition metal phosphides are identified as a promising avenue for the commercialization of lithium–sulfur (Li–S) batteries. In this study, a CoP nanoparticle‐doped hollow ordered mesoporous carbon sphere (CoP‐OMCS) is developed as a S host with a “Confinement–Adsorption–Catalysis” triple effect for Li–S batteries. The Li‐S batteries with CoP‐OMCS/S cathode demonstrate excellent performance, delivering a discharge capacity of 1148 mAh g−1 at 0.5 C and good cycling stability with a low long‐cycle capacity decay rate of 0.059% per cycle. Even at a high current density of 2 C after 200 cycles, a high specific discharge capacity of 524 mAh g−1 is maintained. Moreover, a reversible areal capacity of 6.56 mAh cm−2 is achieved after 100 cycles at 0.2 C, despite a high S loading of 6.8 mg cm−2. Density functional theory (DFT) calculations show that CoP exhibits enhanced adsorption capacity for sulfur‐containing substances. Additionally, the optimized electronic structure of CoP significantly reduces the energy barrier during the conversion of Li2S4 (L) to Li2S2 (S). In summary, this work provides a promising approach to optimize transition metal phosphide materials structurally and design cathodes for Li–S batteries.

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The most promising energy storage devices are lithium-sulfur batteries (LSBs), which offer a high theoretical energy density that is five times greater than that of lithium-ion batteries. However, there are still significant barriers to the commercialization of LSBs, and mesoporous carbon-based materials (MCBMs) have attracted much attention in solving LSBs’ problems, due to their large specific surface area (SSA), high electrical conductivity, and other unique advantages. The synthesis of MCBMs and their applications in the anodes, cathodes, separators, and “two-in-one” hosts of LSBs are reviewed in this study. Most interestingly, we establish a systematic correlation between the structural characteristics of MCBMs and their electrochemical properties, offering recommendations for improving performance by altering the characteristics. Finally, the challenges and opportunities of LSBs under current policies are also clarified. This review provides ideas for the design of cathodes, anodes, and separators for LSBs, which could have a positive impact on the performance enhancement and commercialization of LSBs. The commercialization of high energy density secondary batteries is of great importance for the achievement of carbon neutrality and to meet the world’s expanding energy demand.