We work with many scientists around the world to discover new types of battery chemistries that avoid critical materials, last for longer and can store more energy.
Some promising new types of batteries include: sodium-ion batteries, lithium-sulfur batteries, aluminium and zinc batteries.
Battery Basics
A typical lithium-ion battery consists of two electrodes (cathode and anode) that can store lithium ions, separated by an organic electrolyte which can conduct ions but not electrons.
On charging, ions travel from the cathode to the anode, and the electrons simultaneously pass around the external circuit, creating a flow of current. The reverse occurs during cell discharge, with the flow of electrons providing the current to power our devices.
In a lithium-ion battery, the anode is usually graphite, which is mostly mined in China. The cathode is normally a transition metal oxide containing a mix of lithium, cobalt, nickel, and manganese. These elements are not earth abundant, and their mining practices can be unethical and often result in huge damage to the surrounding environment.
Sodium-ion batteries
Sodium-ion batteries work in a very similar way to lithium-ion batteries, replacing the critical lithium ions with abundant sodium. We can also swap the graphite at the anode with carbon materials made from renewable plant sources, while the commonly used cathodes can replace cobalt and nickel with iron, a far more abundant transition metal. However, state-of-the-art sodium-ion batteries still don’t quite match up to existing lithium-ion batteries in the amount of energy they store, or their long-term performance. Scientists are trying to understand what causes the battery to fade and working on improving the materials inside the battery to improve capacity and stability.
Lithium-sulfur batteries
Lithium-sulfur batteries, while still reliant on lithium, can replace critical materials used in lithium-ion battery cathodes with sulfur, which is cheap, abundant and non-toxic. Lithium-sulfur batteries could store potentially 10 times more energy than lithium-ion batteries but this technology still faces multiple challenges that need to be solved before they can be widely used. Scientists are working on decreasing the amount of lithium needed inside the battery to improve safety and sustainability, and designing better materials at the cathode to speed up charging times and increase battery longevity.
Aluminium-ion batteries
Aluminium is the third most abundant element in the earth’s crust. We can swap lithium for aluminium, with aluminium ions acting as the charge carriers inside the battery. Aluminium-ion batteries are still in a very early stage of development, but typically use graphite or carbon cathodes, aluminium foil anodes, and non-flammable electrolytes. There are still lots of problems to be solved, including improving their long-term stability and safety, due to the highly corrosive electrolyte.
Zinc-ion batteries
Compared to lithium metal, zinc has a higher natural abundance and can theoretically store more charge per volume. Zinc ions are also more compatible with aqueous electrolytes, making them potentially a safer technology. However, zinc-ion batteries generally have a lower efficiency leading to far shorter lifetimes than lithium-ion batteries. Research is being conducted into better electrode materials that can store more energy, and suitable electrolytes for stable ion transfer.
Please get in touch if you want to collaborate on any of these projects!
