High-entropy spinel oxides are promising anode materials for lithium-ion batteries owing to their unique crystal structures, which provide enhanced structural stability, multiple redox-active sites, and three-dimensional Li⁺ diffusion pathways. However, the intrinsic complexity and compositional diversity of high-entropy systems have limited a comprehensive understanding of the correlation between crystal structure, elemental composition, and rate performance, thereby impeding further optimization and practical application. In this study, a high-entropy spinel oxide (Fe_0.2Co_0.2Ni_0.2Cr_0.2Zn_0.2)₃O₄ (FCNCZO) is synthesized to investigate its electrochemical properties. The material delivers a high reversible capacity of 551 mAh g⁻¹ at 500 mA g⁻¹ after 110 cycles and maintains an excellent rate capability of 330 mAh g⁻¹ at a high current density of 2000 mA g⁻¹. Density functional theory calculations indicate that the synergistic interaction among multiple metal elements reduces the bandgap and broadens the d-band width. Moreover, the high-entropy effect promotes metal-oxygen orbital hybridization, facilitates charge redistribution, and significantly enhances rate capability. These findings provide new microscopic insights into the high-entropy effect and demonstrate its potential in designing next-generation high-entropy anode materials with superior rate performance for high-power lithium-ion batteries.

To achieve the goals of the peak carbon dioxide emissions and carbon neutral, the development and utilization of sustainable clean energy are extremely important. Hydrogen fuel cells are an important system for converting hydrogen energy into electrical energy. However, the slow hydrogen oxidation reaction (HOR) kinetics under alkaline conditions has limited its development. Therefore, elucidating the catalytic mechanism of HOR in acidic and alkaline media is of great significance for the construction of highly active and stable catalysts. In terms of practicality, Pt is still the primary choice for commercialization of fuel cells. On the above basis, we first introduced the hydrogen binding energy theory and bifunctional theory used to describe the HOR activity, as well as the pH dependence. After that, the rational design strategies of Pt-based HOR catalysts were systematically classified and summarized from the perspective of activity descriptors. In addition, we further emphasized the importance of theoretical simulations and in situ characterization in revealing the HOR mechanism, which is crucial for the rational design of catalysts. Moreover, the practical application of Pt-based HOR catalysts in fuel cells was also presented. In closing, the current challenges and future development directions of HOR catalysts were discussed. This review will provide a deep understanding for exploring the mechanism of highly efficient HOR catalysts and the development of fuel cells.

In this work, the hierarchical CoNiO₂@CeO₂ nanosheet composites were successfully prepared by a one-step hydrothermal process with a subsequent annealing process for the first time. The CeO₂ nanoparticles successfully deposit on the surface of CoNiO₂ nanosheet, and benefit the improvement of electrical contact between CoNiO₂ and CeO₂. CeO₂ modification improve the reversibility of insertion/extraction of Li-ions and electrochemical reaction activity, and promotes the transport of Li-ions. Benefited of the unique architecture and component, the CoNiO₂@CeO₂ nanosheet composites show high-reversible capacities, excellent cycling stability and good rate capability. The CoNiO₂@CeO₂ (5.0 wt%) shows a charge/discharge capacity of 867.1/843.2 mAh g⁻¹ after 600 cycles at 1 A g⁻¹, but the pristine CoNiO₂@CeO₂ nanosheet only delivers a charge/discharge capacity of 516.9/517.6 mAh g⁻¹ after 500 cycles. The first-principles calculation reveals that valid interfaces between CeO₂ and NiCoO₂ can be formed, and the formation process of the interfaces is exothermic. The strong interfacial interaction resulting in an excellent structure stability and thus a cycling stability of the CoNiO₂@CeO₂ material. This work provides an effective strategy to develop high-performance anode materials for advanced a lithium-ion battery, and the CoNiO₂@CeO₂ nanosheet shows a sizeable potential as an anode material for next generation of high-energy Li-ion batteries.