A major drawback of sodium ion batteries, is their lower energy density compared to lithium-ion, which limits their ability to store as much energy in a given space equal to lithium ion batteries, which hinders their ability to be used in areas demanding high power and prolonged battery life, as they suffer short cycle life and poor reversibility, leading to large capacity loss and low cycling stability.
Sodium ion batteries have potential safety and environmental issues, such as the release of HCN from some sodium ion battery chemistries. Whils’t they are considered safer as they are less prone to overheating however, sodium ion batteries typically have highly flamable liquid electrolytes, which can cause them to potentially catch fire or explode (People often forget a batter has both an Andode Cathode that excite elecrolytes) and are not to be confused with sodium-metal batteries, that have solid electrolytes but, tend to have a much more onferior performance. Sodium ion batteries still present environmental concerns, with substantial amount of resources, contributing to habitat destruction and pollution during extraction and processing. Their disposol also risks toxic chemical leaking into soil and water sources especially countries that have lax enviromental concerns.
Sodium ion batteries charge quickly and will be more suited to mass battery storage farms where size isn’t so important.
CATL have unveiled a type of semi-solid state product which utilise’s a highly conductive biomimetic condensed state electrolytes, with ultra-high energy density cathode materials anode and separator materials, will have an energy density of up to 500 Wh/kg. However it will be used primarily in the aviation sector. Not sure where Rich got 700 Wh/Kg from? However Chinese researchers at the Institute of Physics and Academy of Sciences in China have announced a 711Wh/Kg lithium battery, suggesting they have manufactured practical pouch type rechargeable lithium batteries by using an ultra thick high discharge capacity cathode with an areal capacity exceeding 10 mAh/cm2 and a lithium metal anode.