Salt Could Supercharge Storage Batteries. Humble salt could replace lithium-ion batteries as an energy storage source for a fifth of the cost, and without the ethical concerns, according to new research. A Stanford University study into sodium-ion (Na-ion) battery technology has demonstrated the potential of these batteries to displace lithium-ion, which requires rarer, and more difficult to obtain materials.
The research has found a way to dramatically increase the energy efficiency of the new batteries to more than 87 per cent, but at less than 80 per cent the cost of lithium-ion batteries with equivalent storage capacities.
The new materials would also spare the ethical concerns that can come with lithium-ion due to the locations of mines for the raw minerals.
“A low-cost battery chemistry that can compete with the performance characteristics of lithium-ion batteries could provide the basis for a new class of alternative turn-key (or ready to use) energy storage solutions,” researchers at the Australian Institute for Superconducting and Electronic Materials (ISEM) said.
This need for new battery storage sources is being driven by the forecast escalating price of lithium and cobalt as demand increases for electric vehicles and battery storage technology, University of Wollongong research fellow for the ISEM, Jon Knott said.Stanford’s researchers uses a sodium cathode that has positively charged sodium ions bound to negatively charged myo-inositol ions, and a phosphorous anode. The process creates a greater reversible charge and more storage capacity.
his means it has a longer life and a greater charge than previous sodium batteries, bringing it close to existing lithium batteries in terms of performance
The University of Wollongong’s Shulei Chou demonstrating a sodium-ion energy battery. Photo: Paul Jones
The Clean Energy Council said there were about 6750 battery installations in Australia last year, creating a storage capacity of 52 megawatt hours, and expects the market to treble in 2017.
The Australian Energy Market Operator forecasts a continued steady uptake of battery storage technology after 2021, while South Australia took a massive leap forward last month after launching the construction of the world’s largest single battery storage installation.
“All predictions point towards an explosion in the amount of energy storage applications and capacity in the coming years, such as electric vehicles, residential storage, grid-scale storage, electric aeroplanes etc that will outstrip the supply of lithium-ion batteries, so alternative technologies, such as sodium-ion batteries, can be used in some of these applications,” Dr Knott said.
“The key issue with most lithium-ion chemistries – such as NCA and NMC used in the Tesla electric vehicles and Powerwalls respectively – use significant amounts of expensive cobalt and toxic nickel, which is also expensive.
“Cobalt comes primarily from the Congo, and the process for extracting cobalt from ore is environmentally damaging – and there are serious concerns about the labour used in these cobalt mine.” Sodium should, in theory, hold more power than lithium, however it is less proficient at handling continual charge and discharge cycles, and was less applicable in grid-scale applications until now, with sodium-ion batteries only likely to be 1.5 times the size of lithium-ion batteries of a similar charge.
Lithium has had the advantage of being lighter than sodium and providing more lifetime energy, however it is also exceedingly rare, compared to sodium, of which more than 230 million tonnes were extracted in 2016, with 12 million tonnes extracted in Australia alone. This abundance of material, combined with similar manufacturing processes to lithium-ion batteries, gives sodium-ion an advantage over other alternative storage, “as all of the supply chain, plant and technical know-how developed for lithium-ion batteries can be applied to manufacturing sodium-ion batteries”, Dr Knott said.
“In contrast, technologies such as flow batteries need to not only develop their core technology, but also the manufacturing techniques and processes required to produce that technology.” Closer to home, researchers are working with the Australian Renewable Energy Agency to trial sodium-ion integrated battery storage systems, with a five-kilowatt-hour battery at the net-zero energy Illawarra Flame House, and a 30kWh integrated battery and energy management system at Sydney Water’s Bondi Sewage Pumping Station.