The Lithium Ion Battery Voltage Decay Problem May Be Solved

City University of Hong Kong researchers believe they have achieved a pivotal breakthrough in battery technology that has profound implications for our energy future.

The new development overcomes the persistent challenge of voltage decay and can lead to significantly higher energy storage capacity.

The paper titled “A Li-rich layered oxide cathode with negligible voltage decay”, has been published in Nature Energy. The first authors are Dr Luo Dong, Postdoc, Yin Zijia, PhD student from CityU PHY, Dr Zhu He from Nanjing University of Science and Technology (former Postdoc from CityU PHY), and Dr Xia Yi from Northwestern University/Portland State University, US. The corresponding authors are Professor Ren, Professor Liu, Professor Lu Wenquan from Argonne National Laboratory, US, and Professor Christopher M. Wolverton from Northwestern University. Other collaborators include researchers from the Chinese Academy of Science, Tsinghua University and Lanzhou University.

The team developed novel battery technology with negligible voltage decay, resulting in longer-lasting and more efficient batteries which hold great potential for various applications. Image Credit: City University of Hong Kong. Click the press release link and then the photo for the largest view.

Lithium-ion batteries (LiBs) are widely used in electronic devices, while lithium-(Li) and manganese-rich (LMR) layered oxides are a promising class of cathodes for LiBs due to their high capacity and low cost. However, the long-standing problem of voltage decay hinders their application.

Professor Ren Yang, Head and Chair Professor of the Department of Physics (PHY), Professor Liu Qi, PHY, and their team have addressed the issue by unlocking the potential of LMR cathode materials. In their research, they stabilized the unique honeycomb-like structure within the cathode material, resulting in longer-lasting and more efficient batteries. Their insights are likely to transform the way we power our devices and are set to take the development of high-energy cathode materials to the next stage.

The team’s innovative approach focused on stabilizing the honeycomb structure at the atomic level. By incorporating additional transition metal ions into the cathode material, the team reinforced the honeycomb structure, resulting in a negligible voltage decay of only 0.02 mV per cycle, the first time that LMR cathode material with such a low level of voltage decay has been reported.

Through advanced atomic-scale measurements and calculations, the team found that these interlayer transition metal ions act as a “cap” above or below the honeycomb structure, preventing cation migration and maintaining stability. The structure remained intact even at high cut-off voltages and throughout cycling, ensuring the batteries’ structural integrity.

Professor Liu noted, “Our work has solved the voltage decay problem in the LMR cathode, with a capacity almost two times higher than the widely used cathode materials, ultimately paving the way for more powerful and sustainable energy storage solutions.”

These findings hold great potential for various applications, from powering electric vehicles to portable electronics. The next step involves scaling up the manufacturing process for large-scale battery production.

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The ‘great potential’ comment makes likely sense. There is a strong academic group behind this work and the results look very good.

Lithium ion users tend to think the battery is done when the voltage drops below the requirements of the device the battery powers. However, the capacity might well be there – just not at the useful voltage. Lots of perfectly good low volt lithium ion batteries get tossed for voltage decay.

Thus one hopes that the increase in capacity might well be there as well as a longer lifespan. But there remains a mountain.

Can the tech scale economically? If they make it to market, likely so. But lets not expect a lot of publicity until manufacturers know they can be made for a profit giving consumers benefits.

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