Assembling a cell to test sodium-ion (Na-ion), battery materials in a glove box. Credit: ©Cyril FRESILLON/CSE/CNRS Photothèque
An alternative technology to Li-ion has been designed for application in specific sectors. The researchers have developed the first battery using sodium ions in the usual “18650” format, an industry standard. The main advantage of the prototype is that it relies on sodium, an element far more abundant and less costly than lithium. The batteries have displayed performance levels comparable to their lithium counterparts, and this new technology is already attracting industrial interest. It could be used to store renewable energies in the future, say researchers.
The 1st step was to find the ideal “recipe” for the cathode of the battery.6 partner laboratories of the RS2E were involved in the project with the goal to find the right composition for this sodium electrode. The development of a future prototype was then entrusted to CEA, a member of the RS2E network. In only 6 months, CEA was able to develop the first sodium-ion prototype in the “18650” format, that of the batteries found on the market, i.e. a cylinder 1.8cm in diameter and 6.5cm in height. This should facilitate technology transfer to existing production units.
This 2nd stage made it possible to move from the laboratory scale (synthesis of several grams of cathode material) to the “pre-industrial” scale (synthesis of 1kg batches). It enabled the production of batteries with unmatched power performance levels. Its energy density (quantity of electricity that can be stored by Kg of battery) = 90Wh/kg, a figure already comparable with the first lithium-ion batteries. And its lifespan-the maximum number of charge/discharge cycles that a battery can withstand without any significant loss of performance is > 2,000 cycles. But most of all, these cells are capable of charging and delivering their energy very rapidly. It could be possible to manufacture less expensive batteries.
The next stage of the project is to optimize and increase the reliability of processes with a view to future commercialization. http://www2.cnrs.fr/en/2659.htm
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