KKU looks to monetise battery tech based on rice husks and solar waste

The global trend of electric vehicle (EV) usage is driving an increase in demand for lithium-ion batteries. Automotive lithium-ion battery demand increased by about 65% to 550 gigawatt-hours (GWh) in 2022, from about 330 GWh in 2021.

It is estimated that by 2030, the global production capacity for lithium-ion batteries will reach 5,500 GWh, which is nearly five-fold higher than in 2021. Additionally, there are now over 300 lithium-ion battery manufacturing plants worldwide.

Thailand is experiencing a continuing trend of startups and businesses shifting towards producing batteries for electric vehicles. As well, there innovative manufacturing processes are being explored, such as utilising abundant waste materials in Thailand, including husk and solar cell waste, as materials to produce lithium-ion batteries.

This new technology has the potential to create value for Thai materials in the battery industry while also contributing positively to the environment globally. This innovation won the 2023 award in the public sector category of “best in social and environmental”, from the National Innovation Agency (NIA).

The idea to create lithium-ion batteries from husk and solar cell waste originated at The Battery and New Energy Factory, at Khon Kaen University. It was conceptualised and developed with the inspiration of repurposing leftover materials such as husk and solar cell waste into a material called “nano-silicon”. This material is intended for use as electrodes in lithium-ion batteries.

Thailand has a significant amount of agricultural waste, particularly rice husks, but their utilisation by industry doesn’t yield a high added value, and the generated value doesn’t directly benefit farmers or producers.

Thailand produced around 4,000 tons of solar panel waste in 2022 and it is estimated to increase to 1 million tons in the next 20 years.

Thailand now lacks the processes needed to recycle damaged or end-of-life solar cells into new solar panels or other products. The lack is due primarily to perceived high costs that make the investment not worthwhile. A large percentage of these solar cells, almost 100% in fact, have been disposed of by burying them in landfills. With the floods that accompany high rain, the chemicals and metals in these cells can become an environmental problem.

When researching materials for battery production, the academics considered the benefits that people in the country could gain from using Thailand’s resources to manufacture batteries, with the intent of creating more benefits for the country by going beyond just buying and selling.

The battery has two important and high-value components: the positive electrode, or cathode, which consists of lithium-based materials, and the negative electrode, or anode, which consists of graphite and silicon-based materials.

Currently, large battery manufacturers in Thailand continue to import 100% of these materials for both the positive (cathode) and negative (anode) electrodes from abroad. Thailand lacks the silicon mines found in countries such as Australia and South America.

But where would Thailand obtain silicon? Thailand is an agricultural country and has used solar cells in many areas. A single solar cell panel contains approximately 1 kilogram of silicon. Moreover, rice husks have the highest level of silicon content among all the plants in the nation.

This led KKU researchers to pursue the technology and innovation needed to extract a material called “nano-silicon” from rice husks and solar cell panels to use in producing the negative electrode in lithium-ion batteries. The process of turning rice husks into nano-silicon requires heating at temperatures below 600-700 degrees Celsius, which is considered less energy-intensive compared to traditional methods used by the mining industry.

The nano-silicon derived from rice husks and solar cell panels developed by KKU is currently being incorporated in negative electrode materials in lithium-ion batteries able to support various applications. These applications include portable devices, mobility solutions, and energy storage systems.

The battery and new energy factory at the university now produces and distributes a range of products, including battery packs for electric motorcycles, electric golf carts, and energy storage systems for solar panels.

In addition, there are various electronic devices that popularly use nano-silicon as a component, such as power banks.

Assoc Prof Nongluck Meethong, from the Physics department at KKU, is the director of the Battery and New Energy Factory. She views the production of materials for batteries as part of the global supply chain. Thailand’s target is not limited to domestic battery manufacturers, she said, and is up for the challenge of convincing foreign investors who want to invest in material production within Thailand that there is indeed an opportunity to expand the market.

“Thailand’s opportunity is: How can we produce nano-silicon materials from Thai resources such as rice husks and solar cell waste to a standard that allows us to enter the global battery manufacturing industry value chain?”