As electric vehicles multiply in the global market, so does the concern about the environmental impact of their batteries. In particular, lithium iron phosphate (LFP) batteries, which have a lifespan of about ten years, pose a challenge: their recycling is expensive and not very profitable, as they offer little lithium as a recoverable element.
In this scenario, a team from the University of Wisconsin-Milwaukee, led by Professor Deyang Qu along with graduate student Soad Shajid, proposed an unexpected solution: transforming depleted batteries into agricultural fertilizers.
The process: from lithium phosphate to potassium phosphate
The research, published in The Journal of Physical Chemistry, is based on an ion exchange process that replaces the lithium in the batteries with potassium.
- The lithium phosphate from the cathode is converted into potassium phosphate, a compound with agronomic value.
- The phosphorus comes directly from the battery material.
- Potassium is introduced during recycling.
- By adding nitrogen, an NPK fertilizer is obtained, a formula that combines the three essential elements for crop growth: nitrogen, phosphorus, and potassium.
The great advantage is that this method does not require intensive thermal processes or aggressive chemical treatments, reducing energy consumption and the environmental footprint compared to traditional recycling.
Environmental and economic benefits of battery recycling
The conversion of batteries into fertilizers not only solves a technological waste problem but also:
- Reduces environmental impact, avoiding the storage and disposal of used batteries.
- Decreases the carbon footprint, both in recycling and in fertilizer production.
- Strengthens the circular economy, by utilizing materials that would be considered waste.
- Boosts green employment, creating new professional profiles linked to sustainability.
- Enhances agricultural autonomy, reducing dependency on phosphorus and potassium imports.
In the United States, a large portion of these nutrients comes from countries like Russia, China, or Morocco, creating vulnerability to geopolitical crises and market fluctuations. This method offers a local production alternative, shortening the supply chain and reducing exposure to international risks.
Decentralized application and crop testing
Qu’s team suggests that the technology could be applied in a decentralized manner, installing treatment plants near agricultural or industrial areas where used batteries accumulate. This would reduce logistical costs and promote local job creation.
The project, supported by the United States Department of Agriculture (USDA) and internal university funds, has already demonstrated its feasibility on an experimental scale. The next step will be to test the fertilizer in real conditions:
- An experiment with one hectare of tomatoes, an intensive crop that will allow comparison of the battery-derived fertilizer’s performance with conventional commercial products.
- If the results are equivalent or superior, the initiative could attract the attention of agricultural companies and establish itself as a viable alternative.
Wisconsin as an ideal environment
With its strong industrial and agricultural base, Wisconsin offers the perfect setting to develop this circular recycling model. The combination of both sectors allows progress towards a sustainable production scheme that can also generate technological jobs linked to the energy transition.
A turning point in battery recycling
Although the project is in its initial phase, its approach represents an innovative response to the global challenge of recycling electric vehicle batteries. If it can be scaled and applied on a large scale, it could mark a turning point in the management of technological waste, transforming an environmental problem into an opportunity for agriculture and the circular economy.
