Prussian blue analogs unlock affordable, long-lasting lithium-ion batteries

Prussian blue (PB), a well-known pigment used to dye jeans, has been recognized as an emerging material for next-generation batteries. A team of researchers, led by Professor Hyun-Wook Lee in the School of Energy and Chemical Engineering at UNIST has made a significant breakthrough in the development of low-cost, high-performance lithium-ion batteries (LIBs) using PB, leading to significantly reduced battery prices.

The study, published in Nano Letters, demonstrates a new electrolyte system that overcomes the limitations of PB’s slow kinetics and valence state inactivation, enabling stable and efficient battery operation.

In this study, the research team developed a novel polymeric cathode electrolyte interphase (CEI) layer through a ring-opening reaction of ethylene carbonate triggered by OH^– radicals from structural water. This innovative approach significantly improves the electrochemical kinetics in organic electrolytes, achieving a specific capacity of 125 mAh/g with a stable lifetime over 500 cycles.

The team’s achievement is a game-changer in the development of LIBs, which are crucial for the widespread adoption of electric vehicles (EVs) and other energy storage applications. However, traditional LIBs rely heavily on lithium-containing transition metal oxides as cathode materials, such as cobalt and nickel, leading to high production costs. As a result, the rising price of these resources has caused battery prices to soar.

In contract, PB is a cost-effective and efficient material, comprising iron, carbon, and nitrogen. Its affordability and high ionic conductivity make it an attractive alternative for LIBs. However, not much research has been done on PB so far, partly due to the limitations imposed by the implications of lithium.

Their findings show that PB can be used as a durable and efficient cathode material, showing potential to significantly lower the price of LIBs. Through optimization of performance through electrolyte improvement, its applications are expected to span various battery fields.

“This study marks a significant paradigm shift in the development of cheap cathode materials,” said Professor Lee. “We have successfully transformed PB from an attractive low-cost cathode material to a viable option for commercial use.”

First author Tae-Ung Wi added, “Our research not only overcomes the limitations of existing PB, but also contributes to more efficient and stable battery development in the future.”

This breakthrough has far-reaching implications for the battery industry, paving the way for the widespread adoption of PB as a next-generation cathode material.