Extracting lead from batteries to harvest solar energy

Lead-acid batteries are everywhere – powering cars, aircraft, navigation systems and emergency lighting. Researchers from China’s Xidian University have found a way of recovering lead from spent batteries to produce perovskite – a mineral used in solar cells.

Refined lead is a critical material for low cost and stable batteries, which can contain up to 14kg of the metal. Considering the life cycle of such batteries is two to five years, large volumes of spent lead-acid batteries are now being generated worldwide every year – with the automotive market a huge contributor.

In 2019, the global lead-acid battery market was worth over EUR 37 billion (US$ 40 billion). By 2026, this may well soar by around 50% to almost EUR 55.5 billion (US$ 60 billion).

One-step spin coating

While recycling technologies have come a long way, this growing battery waste stream remains a ‘highly interesting’ research field, according to researchers and scientists at Xidian University in China. They propose a new one-step spin-coating recycling process, described as being both simple and efficient, to revolutionise the solar energy industry.

The new technique is also claimed to be significantly cheaper and less energy intensive compared to other lead-acid battery recycling approaches. ‘And our method causes no secondary pollution,’ says professor Rusen Yang, who specialises in nanotechnology. He reports that anode and cathode lead ‘mud’ reacts with acetic acid to produce high purity lead acetate. Yang’s team used this to fabricate solar cells with a power conversion efficiency reaching 17.83%.

Thanks to the innovation, the perovskite achieves a better crystallisation, yielding dense films with high light-harvesting efficiency. Yang explains that thin-film cells are able to absorb light better than silicon, which is typically used in solar panels. This is why perovskite solar cells are seen as the ‘rising star’ in the field of photovoltaics.

‘We found that the perovskite thin film derived from cathode has the largest particles and the least number of holes,’ Yang reports. ‘Fabrication of perovskite solar cells with lead from spent batteries reduces the environmental impact of battery waste and promotes the development of new energy technology.’