Pressure-Cooked Nanoparticles Improve Lithium-Ion Batteries

David Kisailus, left, and lead author Jianxin Zhu (UC-Riverside)

Engineers at University of California in Riverside discovered a process for improving cathodes in lithium-ion batteries found in today’s electric cars and most electronic devices, and thus their performance. The team from the lab of Riverside’s David Kisailus published their findings in this month’s issue of the journal Crystal Growth and Design (paid subscription required).

The researchers aimed to improve the efficiency of a key component of lithium-ion batteries, the cathode. In lithium-ion batteries, electrons flow from one electrode, known as the anode, to another electrode, the cathode, through an electrolyte. The materials chosen for these components determine the battery’s power and capacity.

Many of today’s lithium-ion batteries use a cathode made of lithium iron phosphate, a material that provides thermal and chemical stability, low toxicity, and low cost. But lithium iron phosphate also does not do a good job in conducting electric power, nor are lithium ions very mobile in this material.

Kisailus and colleagues, including former lab members now at Berkeley and Brookhaven National Labs, devised a process to alter the size and shape of the nanoscale particles in the lithium iron phosphate, making the particles more uniform and get those particles to move faster in a battery cathode. Their process involves heating the material under pressure, in a medium of solvents.

The process resulted in more evenly-sized primary crystalline lithium iron phosphate nanoparticles inside larger secondary particles. The researchers say this composition reduces the path for lithium ions to travel, while maintaining a high density. Lab tests show cathodes made with this new configuration had a larger discharge capacity at higher rates than comparable cathodes made with single-crystal particles.

Kisailus’s team was also able to trace battery performance back to the type of nanoscale structure in the lithium iron phosphate, and the synthesizing process for that structure. The researchers are refining the process to further improve battery performance, and make it more scalable, thus more economically feasible.

Read more:

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• Quality Check Technique Devised for Lithium-Ion Batteries
• Student Devises Lithium Battery for Solar Energy Storage
• Nanotech Solution Boosts Lithium-Ion Battery Performance

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