Japanese company Asahi Kasei has announced the development of a new technology for the pre-lithiation of high-voltage lithium-ion batteries equipped with silicon-based negative electrodes. The technology aims to reduce the irreversible capacity loss that typically occurs during the first charge-discharge cycle, while increasing energy density and lowering the cost of silicon-rich batteries.
The method uses lithium carbonate as an additional lithium source. This material is relatively low-cost and has an established track record of use in the lithium-ion battery industry, but its use in pre-lithiation has been difficult because its decomposition voltage is much higher than the normal operating-voltage range of battery cells.
How does the technology work?
Asahi Kasei uses special electrolyte additives to help decompose lithium carbonate at the normal cell voltages of standard lithium-ion batteries. Lithium carbonate is added in advance to the positive electrode as a sacrificial lithium source, then decomposes during the initial charging process to supply lithium to the cell.
The significance of this step lies in addressing a known problem with silicon-based negative electrodes: these electrodes irreversibly lose a substantial portion of their capacity during the first charge. Compensating for this loss usually requires larger quantities of active material in the positive electrode, increasing material consumption and cost.
Test results and manufacturing potential
In internal tests on an NMC cell, meaning nickel, manganese, and cobalt, containing a negative electrode composed of 90% graphite and 10% silicon oxide, the technology recorded a 10% increase in energy density. The company also said it improved charge-discharge cycle life while reducing cost per watt-hour.
According to the material, the technology does not require major modifications to existing battery manufacturing lines and is expected to be applicable to a wide range of positive- and negative-electrode material systems. This makes the development relevant to battery manufacturers seeking to gradually introduce silicon into negative electrodes without completely rebuilding production lines.
What changes in practice?
If the results are confirmed in independent and production-scale evaluations, the technology could help increase the energy stored in the cell and reduce the amount of positive-electrode material needed to compensate for the initial loss. However, Asahi Kasei has not announced the launch of a final commercial product; rather, it said it will work with customers around the world to conduct proof-of-concept (PoC) evaluations and study practical applications.
The company plans to license the technology and offer flexible collaboration frameworks tailored to each customer’s development stage. This step forms part of the Technology-value Business Creation (TBC) initiative in its medium-term management plan, which aims to convert intangible assets, such as patents, expertise, data, and algorithms, into value through arrangements including licensing.
Asahi Kasei aims to conclude at least 10 new licensing agreements during fiscal years 2025–2027, with a cumulative contribution to profits of 10 billion yen or more by around 2030.