A key part of driving the adoption of renewable energy is driving costs downward, and by experimenting with new cost-effective materials for storage systems scientists continue to make important strides in this area. A team from Cornell University has put forward a compelling example of what this progress can look like, fashioning a 3D electrode out of low-cost aluminum for an environmentally friendly battery with a very long cycle life.
So far as battery materials go, aluminum has a number of appealing characteristics – it's widely abundant in the Earth's crust, it's lightweight and it has high capacity when it comes to storing energy. However, efforts to use it in experimental batteries have been plagued by short circuits and failure, due to adverse chemical reactions with the glass fiber separator that lies between the anode and cathode.
The Cornell team believes it has found a way around this problem, by first combining the aluminum with a substrate made of interwoven carbon fibers. Where typical battery electrodes are only two dimensional, this design creates a 3D structure in which layers of aluminum can be finely controlled and the material accumulates evenly on the carbon structure via covalent bonding as the battery is charged.
“Basically we use a chemical driving force to promote a uniform deposition of aluminum into the pores of the architecture,” says lead author Jingxu Zheng. “The electrode is much thicker and it has much faster kinetics.”
By using this electrode design as part of an experimental battery, the team wound up with a rechargeable device that lasted for up to 10,000 cycles without any signs of failure. This bodes well for its potential as a solution for grid storage of renewable energy, which is often intermittent in nature and calls for low-cost, high-capacity systems that can bank and release energy over a long timeframe.
“A very interesting feature of this battery is that only two elements are used for the anode and the cathode – aluminum and carbon – both of which are inexpensive and environmentally friendly,” Zheng says. “They also have a very long cycle life. When we calculate the cost of energy storage, we need to amortize it over the overall energy throughput, meaning that the battery is rechargeable, so we can use it many, many times. So if we have a longer service life, then this cost will be further reduced.”
The research was published in the journal Nature Energy.
Source: Cornell University
