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Rechargeable Li-CO2 batteries have emerged as promising candidates for next generation batteries due to their low cost, high theoretical capacity, and ability to capture the greenhouse gas CO2. However, these batteries still face challenges such as slow reaction kinetic and short cycle performance due to the accumulation of discharge products. To address this issue, it is necessary to design and develop high efficiency electrocatalysts that can improve CO2 reduction reaction. In this study, we report the use of NiMn2O4 electrocatalysts combined with multiwall carbon nanotubes as a cathode material in the Li-CO2 batteries. This combination proved effective in decomposing discharge products and enhancing cycle performance. The battery shows stable discharge–charge cycles for at least 30 cycles with a high limited capacity of 1000 mAh/g at current density of 100 mA/g. Furthermore, the battery with the NiMn2O4@CNT catalyst exhibits a reversible discharge capacity of 2636 mAh/g. To gain a better understanding of the reaction mechanism of Li-CO2 batteries, spectroscopies and microscopies were employed to identify the chemical composition of the discharge products. This work paves a pathway to increase cycle performance in metal-CO2 batteries, which could have significant implications for energy storage and the reduction of greenhouse gas emissions. 

Rechargeable Li-CO₂batteries have emerged as promising candidates for next generation batteries due to their low cost, high theoretical capacity, and ability to capture the greenhouse gas CO₂. However, these batteries still face challenges such as slow reaction kinetic and short cycle performance due to the accumulation of discharge products. To address this issue, it is necessary to design and develop high efficiency electrocatalysts that can improve CO₂reduction reaction. In this study, we report the use of NiMn₂O₄electrocatalysts combined with multiwall carbon nanotubes as a cathode material in the Li-CO₂batteries. This combination proved effective in decomposing discharge products and enhancing cycle performance. The battery shows stable discharge–charge cycles for at least 30 cycles with a high limited capacity of 1000 mAh g⁻¹at current density of 100 mA g⁻¹. Furthermore, the battery with the NiMn₂O₄@CNT catalyst exhibits a reversible discharge capacity of 2636 mAh g⁻¹. To gain a better understanding of the reaction mechanism of Li-CO₂batteries, spectroscopies and microscopies were employed to identify the chemical composition of the discharge products. This work paves a pathway to increase cycle performance in metal-CO₂batteries, which could have significant implications for energy storage and the reduction of greenhouse gas emissions. 

Abstract We report a single atom Rh₁/CeO₂catalyst prepared by the high temperature (800 °C) atom trapping (AT) method which is stable under both oxidative and reductive conditions. Infrared spectroscopic and electron microscopy characterization revealed the presence of exclusively ionic Rh species. These ionic Rh species are stable even under reducing conditions (CO at 300 °C) due to the strong interaction between Rh and CeO₂achieved by the AT method, leading to high and reproducible CO oxidation activity regardless of whether the catalyst is reduced or oxidized. In contrast, ionic Rh species in catalysts synthesized by a conventional impregnation approach (e. g., calcined at 350 °C) can be readily reduced to form Rh nanoclusters/nanoparticles, which are easily oxidized under oxidative conditions, leading to loss of catalytic performance. The single atom Rh₁/CeO₂catalysts synthesized by the AT method do not exhibit changes during redox cycling hence are promising catalysts for emission control where redox cycling is encountered, and severe oxidation (fuel cut) leads to loss of performance.