The Potential of Na–Air Batteries

Abstract

Sodium–air batteries (SABs) have attracted wide attention in the chemistry society owing to their high energy density, abundant precursor sources, inexpensive materials and reduced manufacture costs, and environmental benignity. This review summarizes the research and progress of the rechargeable SABs based on nonaqueous and aqueous electrolytes. The effects of gas atmosphere, environmental pressure, catalysts, and architectures of the electrodes on the distribution and morphology of discharge products in SABs are also included. The complex and rich sodium electrochemistry of air electrodes is presented, and many electrochemical reaction mechanisms based on the structure design of air electrodes with various catalysts and electrolytes are also summarized. They involve the reversible formation/decomposition reactions of NaO2, Na2O2, Na2CO3, NaHCO3, Na2C2O4, and NaOH. It is a great challenge to seek for highly efficient electrocatalysts, and more stable and less volatile electrolytes to improve the cyclability of nonaqueous SABs. Internal resistance of the cell could be efficiently improved by developing solid electrolytes with high ion conductivity and optimizing the structures of the cells for the high power density of aqueous SABs. How to effectively control the growth and decomposition of discharged products at three‐phase boundary reaction zones by the integration of highly stable electrolytes and optimization of air electrodes is the next challenge urgently needing to be addressed; only then can we realize practical high performance nonaqueous SABs for daily use.

A Critical Review on Superoxide‐Based Sodium–Oxygen Batteries

“…Based upon high specific energy density and high energy efficiency, rechargeable sodium–oxygen (Na‐O 2 ) batteries become a potential candidate for energy storage devices . Compared to lithium‐oxygen (Li‐O 2 ) batteries, Na‐O 2 batteries typically possess higher energy efficiency and are more cost‐effective due to the extensive storage in the earth crust of sodium .…”

Stabilization Perspective on Metal Anodes for Aqueous Batteries

“…Na–air batteries have recently attracted enough attention due to their high theoretical capacity and energy density, and the rich reserves of Na (especially compared to Li). [ 128–132 ] Due to the similar chemical properties of Na with Li, the direct use of Na metal anodes in aqueous solutions will also cause a series of detrimental reactions. [ 133 ] Therefore, for the stable operation of aqueous Na–air batteries, it is also necessary to develop water‐stable Na metal electrodes.…”

Sodium Batteries: A Review on Sodium-Sulfur and Sodium-Air Batteries

“…Sodium air batteries have reported promising results as an alternative metal-air battery and have gained attention as the next generation batteries because of their high specific densities and capacities. Sodium is the sixth most abundant element found on earth with an energy density of about 1600 Wh.kg -1 [48]. The theoretical energy density and specific capacity of sodium are 3164 Wh.kg -1 and 1166 mAh.g -1 , respectively.…”

“…The theoretical energy density and specific capacity of sodium are 3164 Wh.kg -1 and 1166 mAh.g -1 , respectively. The energy cost of rechargeable Li-air batteries is $300-$500 kWh -1 whereas for Na-air batteries, it is $100-150 kWh -1 [48]. Even though lithium and sodium are chemically close, they react very differently with oxygen.…”