A promising new material for solar battery photoanode
(sustainabilityenvironment.com) – What happens when two key technologies of the energy transition are “merged together“? It is what theoretically happens in solar batteries, electrochemical systems capable of storing the sun’s energy directly. In their simplest form these devices consist of three distinct states. The photoanode allows to absorb the photons and accumulate the generated electrons, the transport layer of the gaps, which also works as an internal separator between the two electrodes, and the cathode that “collects” the gaps and works in only one direction to avoid self-discharge.
The latest advances in this field of research come from a joint study of the University of Cordoba, Spain, and the Max Planck Institute for Solid State Research, Germany. The team of scientists has made significant progress in the design of solar batteries thanks to the use of a new material for the anode. It is a compound of 2D carbon nitride, an abundant, non-toxic and easily synthesized material.
Battery storage and photovoltaics come together
“In the group of Professor Bettina V. Lotsch, at the Max Planck Institute, they were able to synthesize a material that could absorb light and store that energy for later use on demand,” explains Alberto Jiménez-Solano, physicist at the University of Cordoba and co-author, “So it occurred to us to use it to create a solar battery”.
To do this, the researchers first had to find a way to deposit a thin layer of that [poly (heptazine imide) potassium 2D carbon nitride] material, creating a stable structure on which to manufacture a photovoltaic device. The structure of the device consists of “a high-transparency glass, which has a transparent conductive coating, and a series of layers of semi-transparent materials (with different functionalities), and another conductive glass that closes the circuit“, says the research.
It is essentially a kind of sandwich composed of several layers whose thicknesses have been studied to maximize both the level of absorption and storage of light. In this case the proposed system can absorb light on both sides as it is semi-transparent. The new solar batteries would be characterized by a great versatility, as it would allow both to obtain a large one-time current (such as that needed for the photographic flash), both a smaller current, which could be sustained over time (like the one needed for a mobile phone).
The work is published in the journal Advanced Energy Materials.