Fudan University has developed a new type of calcium-oxygen battery that can electrochemically charge and discharge at room temperature and operate stably for 700 cycles, with high safety and low cost.The battery was studied by the Peng Huisheng/Wang Bingjie team of Fudan University's Institute of Fiber Electronic Materials and Devices, Department of Polymer Science, Advanced Materials Laboratory, and State Key Laboratory of Polymer Molecular Engineering, together with collaborators such as Wang Yonggang, Zhou Haoshen, and Lu Jun.
On February 7, 2024, the relevant results were published online in the main journal of Nature under the title "Arechargeablecalcium-oxygenbatterythatoperatesatroomtemperature".
According to reports, among batteries based on metallic calcium, calcium-oxygen batteries have the highest theoretical energy density, but they have been unable to charge and discharge stably at room temperature.
The key issues and challenges are,The calcium metal negative electrode has high electrochemical activity, which can easily cause the electrolyte to be reduced and decomposed, and form a passivation layer on the electrode surface, making the calcium metal negative electrode invalid;
at the same time,The air cathode has a high electrode potential, which easily leads to oxidation and decomposition of the electrolyte, and the electrochemical performance of the cathode declines rapidly.
It is still difficult to find an electrolyte that can match the calcium metal negative electrode and adapt to the high electrode potential air positive electrode, which seriously restricts the development of calcium-oxygen batteries.
To address this challenge,The Fudan University team successfully prepared a new electrolyte based on dimethyl sulfoxide/ionic liquid through systematic design of solvent, electrolyte salt, and electrolyte ratio, which effectively met the high requirements of the positive and negative electrodes of the battery and constructed a new calcium-oxygen battery that can operate at room temperature.
This new type of calcium-oxygen battery mainly consists of three parts: metallic calcium negative electrode, carbon nanotube air positive electrode, and organic electrolyte.
It not only optimizes performance and cost, but also takes into account environmental sustainability and application requirements in flexible electronic devices.
Among them, metallic calcium anode not only has a lower cost, but also has a higher theoretical capacity, which is conducive to achieving higher energy density of the full battery.
At the same time, metallic calcium can be further loaded onto the flexible substrate to obtain a flexible metallic calcium negative electrode, laying the foundation for the realization of flexible calcium-oxygen batteries.
The electrolyte is based on a dimethyl sulfoxide/ionic liquid system, which not only exhibits high ionic conductivity at room temperature, but also exhibits stable electrochemical properties, significantly improving the overall safety of the battery.
The cathode material uses a more environmentally friendly carbon material, does not contain expensive precious metal catalysts, and uses oxygen in the air as a reactant, which helps reduce battery manufacturing costs.
At room temperature, this new calcium-oxygen battery can achieve reversible generation and decomposition of discharge products, with a charge-discharge cycle life of up to 700 times.
On this basis, the research team also successfully constructed a calcium-oxygen battery that is both highly flexible and highly safe, providing new ideas for the development of flexible batteries.
Calcium metal has the characteristics of low redox potential and multivalency. Combined with my country's abundant calcium resources, battery systems based on metallic calcium have broad prospects in future energy applications.