Charging With Light: The Photo Battery

A team of researchers from the Indian Institute of Science Education and Research are the latest to declare their hand: a cell powered entirely by light that they have dubbed a ‘photo battery’.

Though far from ready for widespread application, and with no clamour for custom battery packs, unlike in the case of more market-ready lithium-ion products, the photo battery may be an exciting development in battery technology.

Research teams are looking to use the natural power of sunlight in a variety of ways in the energy sector, from fuel development through to charging devices via solar power. As well as having one of the most accessible charge points in the world overhead, the Indian team have found their battery’s titanium nitride chemistry to be much more stable and safer than conventional options such as lithium ion, while taking less time to charge.

Unstable material at the negative anode, though currently the best we have in terms of quality of cycle and mass production, can lead to potentially harmful complications when a cell is defective or becomes damaged.

The photo battery is not yet ready for use in custom battery packs and lacks the capacity to power a mobile phone evenly and reliably. However, it powered both a hand fan and an LED over more than 100 cycles and, under indoor lighting, fully recharged in half a minute. The principle of continuous charge even in ambient light suggests that photo batteries may have a future as clean back-up generators in the event of a total loss of electrical power.

Though the various research efforts going on throughout the world can measure their costs in multiples of thousands of dollars and man hours, often for little in the way of progress, it is important that teams of scientists continue to push for a breakthrough in sustainable energy storage. The team behind the photo battery have taken the first step of putting together a prototype that establishes the titanium nitrate’s beneficial reaction to light.

To develop the chemistry, the team will need to demonstrate that they can power a larger device than an LED with their battery. This may eventually lead to a commercial future and the creation of larger cell formations and custom battery packs of titanium nitrate cells.