A group of researchers at the University of California at Berkeley have developed a zinc-based re-chargeable battery that is far slimmer, lighter and less toxic than the current lithium batteries, can be screen-printed and offers enormous potential for designers of electronic hardware.

Flexible Low-Cost Zinc Battery about to Revolutionise Electronic Device Design?

Lithium is the material in general use today in rechargeable batteries. The main advantage of this technology is the amount of power that can be stored in a small pack. So when the founders of California-based startup Imprint Energy Inc began thinking about the battery of the future, they looked first at the issues arising from the use of lithium. The first problem is the large amount of ‘packaging’ needed. As lithium is very unstable it requires a high degree of protection, which in turn makes such batteries bulky and rigid. In 2012, when the company first raised funds, Imprint Energy introduced its ZincPoly battery technology as a potential competitor to lithium batteries in all aspects, including 50% lower production costs and 50% lower risks than lithium. The thin, flexible ZincPoly battery, which the inventors have engineered to be re-chargeable, is aimed at the booming markets for electronic devices, mobile accessories, and wireless connected objects.

Zinc a handy alternative to lithium

ZincPoly, the patent technology registered by Imprint Energy in 2012, uses a thin sheet of zinc as the battery anode. Zinc is flexible, and can be as energy-efficient as lithium, but the drawback with this element has always been that it did not lend itself to re-chargeable batteries because the formation of chemical accretions in the standard liquid electrolyte inhibited re-charging. In the meantime the Berkeley team have overcome this hurdle by using an electrolyte made of a solid polymer combined with zinc. As zinc is not as reactive or toxic to the external environment as lithium, Imprint Energy is now able to manufacture thinner, less rigid batteries than their lithium rivals, which have hitherto forced electronic hardware manufacturers to design their products according to the shape imposed by the battery – i.e. rectangular and flat.

Long term advantages

Imprint Energy is currently making limited numbers of its ZincPoly batteries on-site using screen-printing technology, an approach which could well become standard in the field.  Imprint Energy’s slim, flexible re-chargeable batteries offer enormous potential for the design of electronic products going forward, with connected objects at the top of the list, helping to overcome the constraints of rigid rectangular power packs. Now that designers’ imagination will no longer be restricted by that shape – which has been the case even for such innovative devices as the Nike FuelBand and the FitBit device – the way is open for flexible screens, wearable devices in unusual shapes. Moreover, Imprint Energy’s ZincPoly battery is a much safer option for creating devices that sit on, or are even embedded in, the body, e.g. to power a heart regulator inside a person’s chest cavity. Zinc does not carry the potentially serious risks to health or life that would arise from a leak of lithium into the human body.

By Simon Guigue