Photo credit: www.sciencedaily.com
Innovative Battery Solutions: Lithium Titanium Phosphate’s Potential in Cold Conditions
Most solid materials tend to expand when heated and contract in cooler temperatures. However, there are exceptions to this norm, including lithium titanium phosphate (LTP), which exhibits the unique property of expanding when the temperature drops. This characteristic could offer a crucial advantage in addressing the performance decline of lithium-ion batteries under cold conditions. A recent study published in the journal Angewandte Chemie by a research team from China highlights the effectiveness of LTP for use in rechargeable battery electrodes.
Lithium-ion batteries, along with other metal-ion based rechargeable systems, are vital for powering everyday devices, electric vehicles, and storing energy from renewable sources like solar and wind. While these batteries function efficiently under warmer conditions, their performance significantly diminishes in colder climates, presenting challenges for various applications, including electric transportation, aerospace missions, and military operations. Traditional solutions such as integrating heaters or enhancing electrolytes and electrode coatings often result in increased costs and complexities in battery manufacturing, or they may impair performance.
A significant factor contributing to the poor performance of these batteries at low temperatures is the slowed diffusion of lithium ions within the electrode materials. To tackle this challenge, researchers from Donghua University, Fudan University in Shanghai, and Inner Mongolia University in Hohhot have explored utilizing electrochemical energy-storage materials that exhibit negative thermal expansion properties. Led by researchers Liming Wu, Chunfu Lin, and Renchao Che, the team examined LTP as a model to demonstrate the advantages of materials with negative thermal expansion in maintaining performance during colder conditions.
Through detailed analysis of LTP’s crystal structure, researchers discovered a three-dimensional lattice comprised of TiO6 octahedra and PO4 tetrahedra, characterized by an open and flexible design. This lattice contains both “cavities” and “channels” that accommodate lithium ions. Notably, as temperature declines, the structure expands along one of its crystal axes. Advanced techniques, including spectrometric methods and electron microscopy, alongside computational modeling, revealed alterations in the vibrational behavior of the atoms at lower temperatures. These changes enhance the transverse vibrations of specific oxygen atoms, increasing the distances between them and effectively broadening the cavities in the lattice. This structural adjustment facilitates the easier storage and movement of lithium ions within the material. Remarkably, even at −10 °C, the diffusion rate of lithium ions remains at 84% compared to the rate at 25 °C. Additionally, electrochemical assessments of carbon-coated LTP at −10 °C demonstrated excellent performance, showcasing high capacity, rapid charge/discharge rates, and strong capacity retention over 1000 cycles.
In summary, materials exhibiting negative thermal expansion, such as lithium titanium phosphate, present exciting opportunities for advancing the performance of lithium-ion batteries in cold environments. This innovative approach holds the potential to mitigate the challenges associated with low-temperature battery operation, making them more reliable for critical applications.
Source
www.sciencedaily.com