With the boom in renewable energy, it's easy to think that all we really need is more solar panels and wind turbines on the grid to make a difference in our current fossil-fuel energy situation, but the weakest link in wind and solar power is actually storage.
Without efficient and affordable energy storage options, large-scale renewable energy installations will still remain just a drop in the bucket when compared to current energy sources (an estimated 95% of energy in the U.S. is from fossil fuels, nuclear power and traditional hydropower). But a recent breakthrough in large-scale battery technology by researchers at Murdoch University may be able to help fill that gap in our power generation systems and enable affordable grid-scale energy storage.
Manickam Minakshi and Danielle Meyrick, of Murdoch’s School of Chemical and Mathematical Sciences, have developed a water-based sodium-ion battery that they say shows excellent potential for affordable, low-temperature storage.
"The central obstacle facing sustainable energy is unreliability. Wind turbines don’t turn on a still day. Solar doesn’t work at night and can be hampered in the day by cloud, dust or snow coverage. To provide power at non-generation times, excess energy needs to be stored in batteries, but storage technologies now being considered, such as molten salt or molten sulfur, work at high temperatures, making them expensive and impractical." - Dr Manickam Minakshi, Murdoch
Dr Minakshi said he was drawn to using sodium for their battery research because its chemical properties were similar to lithium (currently the go-to choice for batteries for portable electronics). Finding materials to use as cathodes and anodes for the batteries was a challenge, though, as sodium's ionic size is well over twice that of lithium. The team found that by using manganese dioxide as cathode and a type of sodium phosphate as the anode, they could build a a safe and affordable battery with a high energy density.
"While the technology is too bulky for portable devices, it has excellent potential for large-scale use, including storing energy from wind turbines and solar farms for later feeding into local electricity grids, as well as use in industry" - Dr Minakshi
The researchers also claim that their new battery has another advantage - it's based on globally abundant and affordable materials, namely sodium, iron and manganese. Dr Minakshi says that their research is ready to move to the next level, which would be large-scale commercialization of the technology.