Batteries are so easy to use that you may not realize they’re continually evolving sophisticated electrochemical devices. Especially now, as researchers around the world race to develop the next best sustainable energy storage apparatus to meet decarbonization goals, new battery ideas are presented almost weekly.
Just to name a few, there are potassium batteries that can clean themselves while charging, redesigned battery architectures to make solid-state batteries more powerful, hybrid power capacitors, and cells made of seawater instead of metals. And today, we have a couple of other advancements to share, this time relating to lithium-sulfur battery breakthroughs.
But first, how does a battery work? Lithium batteries provide electricity by shuffling lithium ions back and forth between two electrodes (a cathode and an anode) through a liquid electrolyte medium. The transfer of ions between these electrodes creates the charge (when the cell is charging) and discharge (when it’s powering something). All batteries work based on this concept – although the materials can vary.
One such variation involves using lithium-sulfur instead of lithium-ions. Such batteries hold great potential because they can store up to five times more energy per weight. However, their lifespan is far shorter because the stress caused by holding so much energy causes the materials to deteriorate and fall apart quickly. That’s why different teams of scientists have been looking for ways to stop this from happening.
So far, a team from Monash University has re-imagined battery architectures to include bridging bonds that give the sulfur particles “some space to breathe.”
Meanwhile, another team from Singapore’s A*STAR’s NanoBio Lab (NBL) has developed a new type of semi-solid electrolyte that improves their safety without compromising their performance.
The cupcake electrolyte is created by dissolving metal precursors and sucrose in water, then heating it until it takes on a brown cupcake shape – hence why they call it the “cupcake method.” The heating process results in the formation of a “liquid-infused porous membrane, made up of highly conductive and chemically stable sheets.” They use this 3D stack of sheets as the electrolyte in the cell, and it allows it to stay stable during charging.
Prof. Jackie Y. Ying, who led the NBL research team, said:
Hybrid quasi-solid electrolytes comprising both liquid and solid components have emerged as a practical compromise to obtain safer batteries while maintaining good performance. However, the high resistance of the solid component has thus far limited the performance of such batteries. To overcome this, we have reengineered the microstructure of the solid component. Our solution eliminates electrolyte leakage and is thermally and mechanically stable.
Our 3D sheet-based framework was found to be crucial for optimal battery performance. Moreover, our system demonstrated outstanding stability under extreme temperatures. These results illustrate the excellent potential of our sheet-based structure as a framework for other semi-solid lithium batteries.
The team put their battery through testing across a range of voltages. The results showed that the cell has fast charging and discharging capabilities, and high capacity. Its performance was among the highest by lithium-sulfur hybrid quasi-solid batteries. The researchers say this unique architecture might be applied to other types of lithium batteries as well.
