Given the poor range of new energy electric vehicles, people are looking forward to new battery technology with large storage capacity and high output power. However, the current lithium ion battery system is limited by its specific energy density, and the power storage is not excellent. No matter how it is fully developed, it is difficult to meet the growing demand of the society for energy storage.
Metal air battery, especially rechargeable alkali metal (mainly lithium and sodium) air battery, because of their unique high energy density (several times or even dozens of times more than lithium ion battery), that is, the strong power storage, has been concerned about as the future of the new generation of battery for new energy vehicles. However, at present, it is still very difficult to develop alkaline metal air batteries for new energy vehicles. The main reasons are: in the process of charging and discharging, lithium and sodium will undergo large volume changes, leading to a rapid decline in battery capacity; In addition, due to the uneven distribution of lithium oxide or sodium oxide generated by the reaction in the electrolyte, dendrites (commonly known as dendritic crystals) are inevitably formed on the surface of metal electrodes, leading to battery power failure and even fire and explosion. There are also alkali metals - lithium or sodium due to the active chemical properties, and
electrolyte electrochemical reaction, resulting in metal electrode consumption, battery failure.
Recently, a new type of lithium-sodium alloy air battery was proposed and developed by a joint research team from changchun yinghua institute of science and technology, jilin university, university of Chinese academy of sciences, university of science and technology of China and Beijing university of aeronautics and astronautics. They based their design on the principle that "the larger the alkali atom radius, the smaller the shielding effect" and "lithium and sodium are similar in nature and have similar electrolyte compatibility". DOL (1, 3-dioxy-pentane ring) was used as the battery additive to control dendrite formation and volume change during discharge and charging of alkali metals. NaCF3SO3/ tetraethylene glycol dimethyl ether, which is corrosion resistant, is used as electrolyte to regulate the battery life by adjusting the proportion of lithium-sodium. The result is a battery capable of 137 cycles, which is much longer than a single sodium electrode. At the same time, when the molar ratio (sodium-lithium) is 6, the impedance in the electrolyte begins to be less than that of the single metal Li (lithium). The cycle performance and electrochemistry of the lithium - sodium alloy air battery were studied. It has wide application value.
This work demonstrates the critical role of lithium alloy anodes and electrolyte additives (DOL) in stabilizing lithium or sodium electroplating/stripping electrochemistry, as well as the production of a lithium-sodium alloy resistant to dendrite formation, oxidation resistance, and crack free. Although the alloy air battery has only just been developed in the laboratory, its excellent electrochemical properties indicate its wide application value. At the same time, it provides a new idea for the development of bimetallic battery.
It is believed that with the efforts of scientists, the new battery system will be established soon. The battery with strong endurance, safety and meeting all kinds of needs will enter our life as soon as possible for our use. With the establishment and application of a new generation of battery system, new energy vehicles will also be widely used and eventually replace fuel vehicles.