The newly developed anode-free battery has a volumetric energy density of 977Wh/L which is 40 per cent higher than the conventional batteries (700wh/L). This means that the battery can run for 630km on a single charge.
Batteries usually change the structure of anode materials as lithium ions flow to and from the electrode during repetitive charging and discharging. This is why the battery capacity decreases over time.
It was thought that if it was possible to charge and discharge only with a bare anode current collector without anode materials, the energy density – which determines the battery capacity – would increase. However, this method had a critical weakness which causes significant swelling of the anode volume and reduces the battery lifecycle. It swelled because there was no stable storage for lithium in the anode.
To overcome this issue, the research team succeeded in developing an anode-free battery in a commonly-used carbonate-based liquid electrolyte by adding an ion conductive substrate. The substrate not only forms an anode protective layer but also helps minimize the bulk expansion of the anode.
The study shows that the battery maintained high capacity of 4.2mAh cm-2 and high current density of 2.1 mA cm-2 for a long period in the carbonate-based liquid electrolyte. It was also proven both in theory and through experiments that substrates can store lithium.
It is anticipated that this battery will accelerate the commercialisation of non-explosive batteries since it maintains high capacity for longer periods. Of course, that assumes that it will ever be commercialised. It seems we write a new type of battery story every week and we are still stuck with the same old lithium versions which history will define as being dangerous.