Can the Li-ion battery ditch the anode altogether?

Conventional lithium-ion batteries shuttle lithium ions back and forth between two electrodes – the anode and the cathode. The cathode is often an oxide, which reversibly reacts with the lithium ions. For example, during discharging, cobalt oxide (CoO₂) ‘absorbs’ lithium ions and electrons to form lithium cobalt oxide (LiCoO₂). During charging, the reverse happens and lithium atoms travel to the anode, finding refuge in the layered carbon structure of graphite – the most-used anode material.

A lot of the improvement in battery capacity and performance over the past decades has been realized by tweaking the chemistry and engineering. Adding a pinch of this or that, making the foils on which the electrodes reside a little thinner – that sort of thing. This has been a delicate balancing act, as changes to improve one aspect usually negatively affect another. Boosting energy density, for example, might reduce lifetime.