The Hunt Is On for Next-Generation Battery Storage Technology

Researchers are on the lookout for new materials to be used in the next generation of batteries that may one day replace current lithium ion batteries. Today, the latter are commonplace and provide a reliable power source for smartphones, laptops and many other portable electrical devices.

Lithium-ion Batteries

A current lithium-ion battery comprises two electrodes — a cathode and an anode. The anode is often made of graphite, the cathode of metal oxides such as cobalt oxide. The lithium ions lodge themselves in these materials during the charging or discharging processes. The two electrodes are separated by a e wall permeable only for lithium ions traveling between the two electrodes, but not for electrons.

During the discharge of a battery, the lithium ions shift from the anode to the cathode. As the electrons do not fit through, they take a detour via an electronic device, which is powered by the resulting electron flux. Electrons and ions meet again in the cathode. When the battery is charging, the ions and electrons are enforced to flow in the opposite direction. For the battery to work effectively and for a long time, the ions need to be able to move in and out of the electrode materials easily. The shape and size of the electrode materials should not change much through the recurrent absorption and release of the ions.

On the one hand, however, electric mobility and stationary electricity storage demand a greater number of more powerful batteries; and the high demand for lithium may eventually lead to a shortage of the raw material. This is why conceptually identical technology based on sodium-ions will receive increasing attention in coming years. Contrary to lithium batteries, researched for more than 20 years, much less is known about materials that can efficiently store sodium ions.

Antimony Electrodes?

A team of researchers from ETH Zurich and Empa headed by Maksym Kovalenko may have come a step closer to identifying alternative battery materials: they have become the first to synthesise uniform antimony nanocrystals, the special properties of which make them prime candidates for an anode material for both lithium-ion and sodium-ion batteries. The results of the scientists’ study have just been published in Nano Letters.

For a long time, antimony has been regarded as a promising anode material for high-performance lithium-ion batteries as this metalloid exhibits a high charging capacity, by a factor of two higher than that of commonly used graphite. Initial studies revealed that antimony could be suitable for rechargeable lithium and sodium ion batteries because it is able to store both kinds of ions. Sodium is regarded as a possible low-cost alternative to lithium as it is much more naturally abundant and its reserves are more evenly distributed on Earth.