prevents the diffusion of polysulfides and reduces the shuttle effect . Graphene in particular shows promise , with research into a graphene aerogel ‘ catholyte ’ being only one of many developments attempting to merge the two exciting technologies of graphene and Li-S batteries . Another problem with polysulfides is that they react with the standard carbonate electrolytes used in the batteries . As a result , carbonates have been replaced with ether electrolyte in Li-S cells , but this can lead to cell failure due to the low boiling point of the ether electrolytes . Researchers at Drexel University recently developed a cathode formed from carbon nanofibres with monoclinic gamma-phase sulfur that does not form polysulfides , resulting in a very stable cell that can utilise industry-standard carbonate electrolytes . There are signs that commercialisation of Li-S is on the horizon . The Californian company Lyten is aiming to begin commercial production of a Li-S battery in 2025 / 26 . Mullen Technologies also plans to produce over 100,000 EVs equipped with Li-S pouch cells within the next five years .
Sodium-ion
Replacing the charge-carrying lithium ions with sodium would provide a battery , which is cheaper , safer and more sustainable . Sodium is much more naturally abundant than lithium
– there are 39.34 grams of sodium in every 100 grams of table salt . A viable sodium-ion cell would therefore mean massive cost reductions for producers and reduced demand for scarce resources . Although the idea of sodium-ion cells has been investigated for just as long as Li-ion , intrinsic problems with sodium-based batteries have stifled any chance of commercial success . The first-cycle efficiency of sodium cells is generally poor , with a loss of around 20 % of the available capacity on first charge . Sodium-ion cells deliver a smaller gravimetric energy density than lithium-ion , meaning fewer kWh per kg of battery weight . This is clearly not ideal for a battery destined for use in an EV where weight savings are crucial for viable range . However , the commercialisation of a sodium-ion battery no longer seems such an outlandish prospect , as several businesses and research groups have announced developments which address some of these problems with sodium-based cells . Contemporary Amperex Technology ( CATL ), the largest Chinese LIB manufacturer has recently announced its target to bring a sodium-ion battery to market by 2023 . Although the cells still do not achieve an energy density comparable with that of LIB alternatives , they provide improved performance in cold temperatures , fast charging capabilities and high power delivery . In any case , gravimetric energy density becomes less important when considering applications such as stationary storage ( for example , to store energy from renewable sources of generation to smooth out grid supply ) or structural batteries ( where structural elements of buildings , such as walls and floors , contain batteries ). The improved prospects for sodium-ion technology are being recognised across the globe . Reliance New Energy Solar , a wholly owned subsidiary of the Indian multinational conglomerate Reliance Industries , recently purchased British sodium-ion battery tech company Faradion for £ 100 million , with another £ 25 million earmarked to accelerate the commercialisation of the battery . Reliance intends to use Faradion ’ s technology for energy storage at its planned gigafactory in Jamnagar , western India . Mukesh Ambani , chairman of Reliance said : “ The sodium-ion technology developed by Faradion provides a globally leading energy storage and battery solution which is safe , sustainable , provides high energy density and is significantly cost-competitive . In addition , it has wide use applications from mobility to grid scale storage and back-up power .”
Lithium metal is at the heart of most EV batteries
78 SPECIALITY CHEMICALS MAGAZINE ESTABLISHED 1981