Li-air batteries attract abundant attention in recent years with superior performance, and have largely replaced traditional methods of energy storage. The main objective of Li–air battery is to ...provide long-range electric-vehicles, while functioning as an environmentally friendly and compact energy storage solution. They offer the highest theoretical energy density (3500 Wh/kg), almost 20% higher than the ordinary Li-ion batteries. Nonetheless, Li-air batteries still face numerous issues, the most serious of which are high overpotential and parasitic reactions. Several redox mediators (RM) have been studied in order to reduce the high overpotential and the influence of side reactions. RM function in the electrolyte as soluble catalysts, limiting the formation of singlet oxygen while promoting the formation of discharge product Li2O2. This research primarily focuses on the optimization of Li-air cells with different redox mediators in conjunction with appropriate electrolyte, as a result reducing overpotential, parasitic byproducts and increasing efficiency. Under standard electrolytic conditions, ruthenocene exhibits high stability by completing 83 cycles, thus outperforming the other mediators being investigated. Further, di-tert-butyl-1,4-benzoquinone is more commonly used for discharge reaction and has been shown to increase the capacity of Li–O2 batteries by 80 times. This study reconfirms lithium bis(trifluoromethylsulfonyl) imide in tetraethyleneglycol dimethylether as the most stable electrolyte.
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•LABs offer high energy density but pose overpotential and parasitic reactions.•Redox mediators or soluble catalysts are studied to reduce overpotential issues.•Ruthenocene is highly stable and outperforms all other mediators.•DBBQ is commonly used for discharge and increases the capacity of LABs 80 times.
Entre todos los tipos de baterías, las de litio-aire (LAB) se consideran las más eficaces debido a su mayor densidad energética, de unos 11.140 Wh/kg, pero las LAB se enfrentan a algunos problemas ...importantes, como un gran sobrepotencial, una vida útil deficiente, una baja densidad de corriente y una menor eficiencia energética. La solución a estos problemas depende principalmente de la selección adecuada de un electro catalizador. Un nuevo enfoque para utilizar un electrocatalizador bifuncional produjo excelentes resultados. En este caso, se ha considerado el compuesto CO.sub.3O.sub.4/alfa - MnO.sub.2 como catalizador bifuncional, ya que el óxido de cobalto obtuvo buenos resultados en el proceso de Reacción de Evolución de Oxígeno (OER), mientras que el óxido de manganeso obtuvo buenos resultados en el proceso de Reacción de Reducción de Oxígeno (ORR). En este trabajo se utiliza un sencillo proceso hidrotermal de dos pasos para sintetizar CO.sub.3O.sub.4/alfa - MnO.sub.2. Este trabajo se centra en el comportamiento del electrocatalizador compuesto cuando se depositan porcentajes variables de óxido de cobalto (5%, 10%, 15% y 20%) sobre los nanorods de óxido de alfa-manganeso. Se examinan las características primarias de cada muestra con distintos porcentajes de óxido de cobalto y se compara el rendimiento de cada una de ellas entre sí. Las muestras se someten a diversas técnicas de ensayo, como la voltamperometría cíclica (CV), la voltamperometría de barrido lineal (LSV), la difracción de rayos X (DRX) y la microscopía electrónica de barrido (SEM). La combinación de óxido de cobalto y óxido de manganeso mostró un efecto sinérgico y funciona como un electrocatalizador bifuncional. A medida que aumenta el porcentaje de CO.sub.3O.sub.4 depositado sobre el nanorod alfa - MnO.sub.2, éste se comporta más como un electrocatalizador OER dando lugar a una disminución del potencial de carga. Este trabajo ayudará a encontrar la cantidad óptima de CO.sub.3O.sub.4 que debe depositarse sobre los nanorods de alfa - MnO.sub.2 para obtener un electrocatalizador bifuncional (ORR/OER) eficiente.
Among all type of batteries, Lithium Air Batteries (LAB) are considered to be the most effective due to their highest energy density of around 11900 Wh/kg but there are some major issues are being ...faced by LAB such as large overpotential, poor cycle life, low current density, and decreased energy efficiency. The solution to these issues is primarily dependent on the proper selection of an electrocatalyst. A new approach for using a bi-functional electrocatalyst produced excellent results. Here, Co3O4/α-MnO2 composite has been considered as a bifunctional catalyst because cobalt oxide performed well in the Oxygen Evolution Reaction (OER) process while manganese oxide performed well in the Oxygen Reduction Reaction (ORR) process. A simple two-step hydrothermal process is used in this work to synthesize Co3O4/α-MnO2. This work focuses on the behavior of the composite electrocatalyst when varying percentages of Cobalt oxide (5%, 10%, 15%, and 20%) are deposited on the alpha-Manganese Oxide nanorods. The primary characteristics of each sample with different percentages of Cobalt Oxide are examined, and the performance of each sample is compared to one another. Several testing techniques like Cyclic Voltammetry (CV), Linear Sweep Voltammetry (LSV), X-Ray Diffraction (XRD), and Scanning Electron Microscopy (SEM) are performed on the samples. The combination of cobalt oxide and manganese oxide showed a synergistic effect and work as a bifunctional electrocatalyst. As the percentage of Co3O4 deposited on the α-MnO2 nanorod increased, it behaves more like an OER electrocatalyst leading to a decrease in charging potential. This work will help in finding an optimum amount of Co3O4 that should be deposited on α-MnO2 nanorods to get an efficient (ORR/OER) bifunctional electrocatalyst.
