A high-efficiency, low-cost solar cell can be made using the lead recovered from discarded lead-acid car batteries. The development could prove a boon to both the environment and human health, say the MIT researchers behind this innovation.
Many believe that the new class of solar cells called perovskites have the potential to transform the solar industry: the starting ingredients are readily available and can easily be processed at low temperatures. The fabricated solar cells themselves are thin, lightweight and flexible, making them ideal for applications such as windows and building facades.
But one of the biggest stumbling blocks to producing perovskite solar cells on a commercial scale is that the most efficient of them all contain lead, explains MIT in a news article. While lead in consumer devices can be encapsulated in other materials to prevent it from escaping and contaminating the environment, the real concern is lead mining and refining. According to the article, these raise serious health and environmental issues from releasing toxic vapours and dust into the environment to high energy consumption and greenhouse gas emissions.
This is where two MIT researchers stepped in. Angela Belcher, a professor of biological engineering and material science and engineering, and Paula Hammond, a professor in engineering, discovered that it is possible to make perovskite solar cells using lead recovered from discarded lead-acid batteries.
And it turns out that the recovery process is remarkable simply, involving just three main steps: recovering the lead from the electrodes of the car battery, synthesising lead iodide from the collected materials, and then turning it into a thin film of perovskite and integrating it into a functional solar cell.
Through various laboratory experiments, the researchers also determined that solar cells made from recycled lead are just as efficient as those made with high-purity starting materials. “People who are skilled in fine-tuning these solar cells to get 20 per cent efficiencies would be able to use our material to get the same efficiencies,” says Belcher.