Rational design and understanding of the intrinsic mechanism are critical to develop highly active and durable electrocatalysts. In this study, a series of bi-metallic boride catalysts based on Ni and Co were prepared, and their activities were evaluated. The synthesised Co–10Ni–B catalyst exhibited excellent activity for water splitting in a 1 M KOH electrolyte. The overpotential was 330 mV at a current density of 10 mA cm⁻², better than previously reported mono-metallic borides and even IrO₂. The synergistic effect of Co and Ni was proved by X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy. The facile formation of critical intermediates CoOOH and NiOOH during the catalytic processes and a significant increase in surface area owing to the introduction of a second metal into mono-metallic boride were attributed to the superior catalytic performance of catalysts for the oxygen evolution reaction. A Co–10Ni–B-sp catalyst with a higher surface area than the Co–10Ni–B catalyst was also synthesised to evaluate the effect of a high surface area on the catalytic activity. A lower overpotential of 310 mV at a current density of 10 mA cm⁻² was achieved.

As an important component, the anode determines the property and development of lithium ion batteries. The synthetic method and the structure design of the negative electrode materials play decisive roles in improving the property of the thus-assembled batteries. Si@C compound materials have been widely used based on their excellent lithium ion intercalation capacity and cyclic stability, in which the in-situ synthetic method can make full use of the structural advantages of the monomer itself, thus improving the electrochemical performance of the anode material. In this paper, the different preparation technologies and composite structures of Si@C compound materials by in-situ synthesis are introduced. The research progress of Si@C compound materials by in-situ synthesis is reviewed, and the prospect of future development of Si@C compound materials has been tentatively commented.

Polyhedral oligomeric silsesquioxane (POSS)-derived Si@C anode material is prepared by the copolymerization of octavinyl-polyhedral oligomeric silsesquioxane (octavinyl-POSS) and styrene. Octavinyl-polyhedral oligomeric silsesquioxane has an inorganic core (-Si₈O₁₂) and an organic vinyl shell. Carbonization of the core-shell structured organic-inorganic hybrid precursor results in the formation of carbon protected Si-based anode material applicable for lithium ion battery. The initial discharge capacity of the battery based on the as-obtained Si@C material Si reaches 1500 mAh g⁻¹. After 550 charge-discharge cycles, a high capacity of 1430 mAh g⁻¹ was maintained. A combined XRD, XPS and TEM analysis was performed to investigate the variation of the discharge performance during the cycling experiments. The results show that the decrease in discharge capacity in the first few cycles is related to the formation of solid electrolyte interphase (SEI). The subsequent rise in the capacity can be ascribed to the gradual morphology evolution of the anode material and the loss of capacity after long-term cycles is due to the structural pulverization of silicon within the electrode. Our results not only show the high potential of the novel electrode material but also provide insight into the dynamic features of the material during battery cycling, which is useful for the future design of high-performance electrode material.

Aiming to find suitable electrolytes for electric double layer capacitor (EDLC), the relationship between the formation velocity of electric double layer and the specific capacitance in different electrolyte (H₂SO₄, KOH, KCl, NH₄Cl, and LiOH) solutions was investigated by cyclic voltammetry and AC impedance with varying frequency and potential, which was also analyzed based on Stern model and Gouy-Chapman diffusion layer model. It shows that the capacitance is positively correlated with the formation velocity of the electric double layers, which is affected by the type of ions applied, the concentration of the electrolyte solution, and the potential and frequencies as well. The electrolyte solutions of 6 mol/L KOH and 4 mol/L H₂SO₄ provide the largest capacitance, reaching 214 and 186 F/cm², respectively. Both 6 mol/L KOH and 4 mol/L H₂SO₄ solutions are suitable electrolytes for EDLC applications using Pt as electrodes.