Bismuth-based materials are prevalent catalysts for CO₂ electroreduction to formate, enduring high hydrogen evolution reactions and inadequate activity and stability. Herein, we reveal that in-situ electrochemical transformation of Cu₂BiS_x solid solution into Bi/Cu_xS_y heterointerfaces, which can stabilize the intermediates and achieve highly selective and consistent CO₂ electroreduction. It shows over 85% Faraday efficiency (FE) of formate with a potential window of −0.8 to −1.2 V_RHE (RHE: reversible hydrogen electrode) and a stability above 90% over 27 h in H-type cell at −0.9 V_RHE. It maintains more than 85% of FE_formate at the current density of −25 to −200 mA·cm⁻², and has stability of about 80% of FE_formate at least 10 h at −150 mA·cm⁻² in flow cell. In-situ Fourier transform infrared (FT-IR) spectroscopy measurement confirms that the preferred route of catalytic reaction is to generate *CO₂⁻ and *OCHO intermediates. The density functional theory (DFT) calculations illustrate that heterointerfaces facilitate the prior process of CO₂ to HCOOH through *OCHO by additional Bi hybrid orbitals. This study is expected to open up a new idea for the design of CO₂ electroreduction catalyst.

Recently, rechargeable zinc-ion batteries have been considered as the future development direction of large-scale energy storage due to their low price, safety, environmental friendliness, and excellent electrochemical performance. However, high-capacity, long-cycle stable cathode materials that can meet the demand are still to be developed. Herein, the hollow mesoporous ZnMn₂O₄/C microsphere cathode material with carbon nanotubes embedded in the shell was prepared by spray pyrolysis for the first time. Its capacity remained at 209.71 mAh·g⁻¹ after 150 cycles at a rate of 0.5 A·g⁻¹, and still maintained a specific capacity of 100.06 mAh·g⁻¹ at a rate of 1 A·g⁻¹ after 1,000 cycles. The outstanding performance is attributed to the hollow structure that can effectively buffer large volume changes caused by ion intercalation and deintercalation, excellent porosity, cationic defects, and high electrical conductivity of carbon nanotubes and its strong adsorption to ZnMn₂O₄ nanoparticles.

The yolk–shell structure has a unique advantage in lithium-ion batteries applications due to its ability to effectively buffer the volume expansion of the lithiation/delithiation process. However, its development is limited by the low contact point between the core and shell. Herein, we propose a general strategy of simultaneous construction of sufficient reserved space and multi-continuous active channels by pyrolysis of two carbon substrates. A double-shell structure consisting of Co₃O₄ anchored to hollow carbon sphere and external self-supporting zeolitic imidazolate framework (ZIF) layer was constructed by spray pyrolysis and additional carbon coating in-situ growth. In the process of high-temperature calcination, the carbon and nitrogen layers between the shells separate, creating additional space, while the Co₃O₄ particles between the shells remain are still in close contact to form continuous and fast electron conduction channels, which can realize better charge transfer. Due to the synergy of these design principles, the material has ultra-high initial discharge capacities of 2,183.1 mAh·g⁻¹ at 0.2 A·g⁻¹ with capacity of 1,121.36 mAh·g⁻¹ after 250 cycles, the long-term capacities retention rate is about 92.4% after 700 cycles at 1 A·g⁻¹. This unique channel-type double-shell structure fights a way out to prepare novel electrode materials with high performance.

Molybdenum phosphide is a potential hydrogen evolution reaction (HER) catalyst. However, traditional high-temperature phosphating preparation methods are prone to damage of material morphology and agglomeration. Using the carbon skeleton to limit the size and morphology of MoP and to improve the conductivity of the material is an effective method to improve the performance of the catalyst. However, there is a lack of research on the effect of carbon skeleton and MoP composite structure on the catalytic mechanism of HER. We coated ZIF-8 on the surface of MoP nanorods, and obtained open N-doped carbon-coated porous MoP nanorods (N/C/MoP) through carbonization and phosphating. Studies have shown that the ZIF-8 coating effectively limits the size and morphology of the material and avoids agglomeration. Under alkaline conditions, N/C/MoP has a low overpotential of 169 mV for HER at 10 mA/cm², which is 55 mV lower than MoP without a carbon layer. At the same time, its Tafel slope (51.3 mV/dec) is smaller than Pt/C (59.9 mV/dec), and it has good stability. Density functional theory (DFT) studies have shown that under alkaline conditions, there is a synergistic effect between the open N-doped carbon layer and the exposed MoP active surface, which reduces the activation energy of water and improves the catalytic performance of HER. It is worth noting that a tight coating will hinder the exposure of active sites and reduce catalytic activity.

Vesicular lithium vanadium phosphate/carbon hollow mesoporous microspheres were fabricated using a facile polyvinylpyrrolidone-assisted aerosol-spray-assisted method and subsequent heat-treatment. While changing the content of polyvinylpyrrolidone, we found that carbon content was adjustable on the surface of lithium vanadium phosphate. By optimizing the carbon content among the composites, the electrochemical performance can be enhanced significantly. The results of electrochemical performance tests suggested that the samples exhibited good cycle performance and high discharge capability in the voltages between 3.0–4.8 V. The observed excellent electrochemical performances could be attributed to the proper content of carbon coating and the vesicular hollow mesoporous microsphere structure, increasing the transmission rate of lithium ions and reducing the structural change during charging and discharging effectively.

Porous hollow Co₃O₄ microspheres have been synthesized from a mixed cobalt nitrate and urea solution through spray pyrolysis followed by calcination at 600 ℃ in air. This porous hollow Co₃O₄ is assembled by nanoparticles and exhibits variable porosity depending on the amount of gas in the system. In pyrolysis process, urea continuously decomposes into gaseous components, which act as a template to control the porous structure. The amount of gas escaping from precursor droplets can directly influence the porosity of the microspheres and the size of the nanoparticles controlled by the ratio of urea to cobalt nitrate. Electrochemical measurements show that the performance of the porous hollow Co₃O₄ microspheres is related to the porosity and size of the nanoparticles. The sample with optimal porosity delivers a high first charge capacity of 1, 417.9 mAh·g^-1 at 0.2C (1C = 890 mA·g^-1), and superior charge cycle performance of 1, 012.7 mAh·g^-1 after 100 cycles. In addition, the optimized material displays satisfactory rate performance of 1, 012.4 mAh·g^-1 at 1C after 50 cycles and 881.3 mAh·g^-1 at 2C after 300 cycles. Superior charge/discharge capacity, excellent rate performance and high yield achieved in this study is promising for the development of high-performance Co₃O₄ anode materials for lithium-ion batteries.

The sluggish oxygen evolution reaction (OER) is an important half-reaction of the electrochemical water-splitting reaction. Amorphous Fe/Ni composite oxides have high activity. In this work, we modified the aerosol spray-assisted approach and obtained amorphous Fe-Ni-O _x solid-solution nanoparticles (Fe-Ni-O _x -NPs) approximately 20 nm in size by choosing iron/nickel acetylacetonates as raw materials instead of inorganic salts. The small-sized Fe-Ni-O _x -NPs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) analysis, energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). Furthermore, an investigation of electrochemical OER performance suggests that the small-sized Fe-Ni-O _x -NPs have higher activity than the large-sized Fe-Ni-O _x -MPs. A small overpotential of 0.315 V was demanded to obtain a working current density of 50 mA/cm², and the Tafel slope was as low as 38 mV/dec.