Today, portable electronics are generally powered by batteries. However, the utility of batteries is limited by the need to frequently charge them. A device that could simultaneously harvest and store energy would free product users from this inconvenience and could render the ‘dead phone’ a thing of the past.
The current approach for harvesting and storing energy is to use two separate devices, one for harvesting and another for storage. For example, a solar panel/battery combination. This technology has a range of disadvantages, including difficulties with portability and energy efficiency. A recent review in Advanced Science, details recent efforts to enable the integration of energy harvesting and storage using a shared electrode.
The review focusses particularly on the harvesting and storing of solar energy in thin, fibre-type devices. The ultimate goal of this line of research is that these devices could made into threads and be woven into normal clothing. The wearer would then be able to charge portable devices and gadgets directly.
The study’s leader Prof. Jayan Thomas emphasises the convenience of such devices, saying “By developing an integrated energy harvesting and storing fabric, we address one of the pressing present-day challenges of wearable devices, an easily portable self-powering energy unit”
The review makes it clear however, that the advantages of this technology are not by any means limited to convenience. By minimising the distance between the sites of energy collection and storage, energy loss can be considerably lessened, making the technology quite efficient.
While these devices offer higher efficiency than existing approaches to energy collection and storage, they are not without drawbacks. Presently, they suffer from low energy density. This means that the collected charge cannot be used for a long term device operation. Scientists in the field are seeking to overcome this issue by exploring new materials and architectures that improve this key parameter.