A research team from South Korea recently demonstrated a new type of sodium ion rechargeable battery at room temperature and high energy density using a sulfur dioxide-based inorganic fusion cathode electrolyte that serves as both a sodium ion-conducting electrolyte and a cathode material.
According to the total mass of the catholyte and the carbon electrode, the discharge capacity of the new sodium ion battery is 153 mAh / g and the operating voltage is 3V. The battery pack has excellent charge and discharge performance under high current conditions, as well as the charge-discharge cycle performance Very outstanding, able to more than 300 times. Of particular note is that the new inorganic liquid electrolyte has flame resistance and self-reconfiguration features that help accelerate the commercialization of sodium ion rechargeable batteries.
The researchers constructed a battery containing 2032 sodium-sulfur dioxide button cells using a sodium metal anode and a long and short carbon cathode. The liquid electrolyte was a sodium aluminum chloride and sulfur dioxide complex solution. Based on a discharge rate of 0.1 coulomb carbon cathode, the discharge capacity of the cell is about 1800 mAh / g (or 4.1 mAh / cm), which compares favorably with the conventional commercial Li-ion battery (3-5 mAh / Square centimeters) is basically equivalent, much better than previously reported performance of lithium-ion batteries and sodium-oxygen batteries. The discharge capacity of the sodium-sulfur dioxide battery can reach 897 mAh / g, even at high current densities of 5 coulombs.
However, the energy efficiency between charge and discharge is only about 80%, this point needs to be further improved. Sodium-sulfur dioxide battery after repeated charge and discharge cycles, the storage capacity decay rate is relatively low; each discharge process energy exhausted, and high-coulomb rate of high-current charge and discharge conditions, after 100 cycles of storage capacity to reach 75% of new battery pack.
The cell chemistry is a highly reversible redox reaction between sulfur dioxide and sodium tetrachloroaluminate. A composite inorganic electrolyte consisting of sodium aluminum chloride and sulfur dioxide ensures the reliability of the sodium-sulfur dioxide battery, The safety of the life cycle is also guaranteed.