The recent announcement by Tesla of Powerwall, its new lithium-ion (Li-ion) based residential battery storage system, has caused quite a stir. It even raises the possibility of going off-the-grid, relying upon solar panels to generate electricity, and storing it with their own battery and using it on demand.

Yet the lithium-ion technology used by Tesla isn’t the only one on offer. In fact, each of the various battery technologies has its own strengths and weaknesses, and some might even be superior to lithium-ion for home installations. Here is a quick survey of current battery technologies, and some that are in development.

Battery power

All rechargeable batteries consist of two electrodes separated by an electrolyte. Two different reversible chemical reactions occur at the two electrodes. While charging, an “active species” – i.e. a charged molecule, such as lithium ions for Li-ion batteries – is stored in the anode. During discharge this migrates to the cathode. The chemical reaction occurs at a potential which can be used to power an external circuit.

Each type of battery technology can be judged on a number of criteria, such as:

• recyclability, which is the number of times it can be charged and discharged
• energy density, which is a measure of the energy stored per unit mass, measured in Watt-hours (a measure representing a Watt of power output over an hour) per kilogram (Wh/kg)
• specific density, which is the energy stored per unit volume, measured in Watt-hours per litre (Wh/l).

Which technology is best suited for a particular application depends on the demands of that role.

You can read the rest of this article on The Conversation. 

Dr Cameron Shearer is a Research Associate in Physical Sciences at Flinders University.