The underlying problem is one of geometry and transport. In a conventional battery, the cathode is a relatively thin layer of active material coated onto a metal current collector. Increasing the thickness of that layer packs in more of the energy-storing material and reduces the relative weight and volume taken up by current collectors and separators, which is exactly what designers of long-range electric vehicles want. But as the electrode grows thicker, lithium ions must travel farther through a crowded, tortuous pore network to reach the deeper regions. Transport slows, electrochemical reactions become concentrated near the electrode surface, and a large fraction of the stored energy becomes effectively inaccessible during fast charging or discharging. The KRICT team describes this as a lithium-ion traffic jam, and their additive is designed to clear it.

The manufacturing route matters as much as the chemistry. Most electrodes today are made by a wet process: cathode active materials, binders, and other components are mixed into a solvent, coated onto the current collector, and then dried. In thick electrodes, the drying step causes the binder to migrate toward the surface, leaving an uneven distribution of components through the film. Dry electrode manufacturing eliminates the solvent and the drying stage entirely, which avoids that migration and, as the researchers note, has significant potential to reduce manufacturing costs, energy consumption, and production space by removing solvent-drying and recovery processes. Dry processing alone, however, does not solve the rising resistance to lithium-ion transport that comes with thicker electrodes, which is where the new additive comes in.

Graphitic carbon nitride is a porous, nitrogen-rich material, and the team exploited its surface chemistry in a specific way. Nitrogen atoms on the surface of the g-C3N4 particles temporarily capture and release passing lithium ions through the formation of transient lithium-nitrogen bonds. The researchers compare the effect to placing intermediate transfer hubs inside a large building: instead of a visitor struggling across the whole structure in one effort, the hubs break the journey into easier stages. In electrochemical terms, the additive helps lithium ions shed the solvent molecules of the electrolyte that surround them and enter the cathode active material more readily. The porous structure of the additive also improves electrolyte wettability, allowing the liquid electrolyte to penetrate the thick film more effectively and promoting a more uniform distribution of lithium ions throughout the electrode.

The quantitative gains reported in the study are striking. The activation energy required for lithium-ion charge transfer, the energy barrier ions must overcome to enter the cathode material, fell by 56 percent, from 49.8 to 22.1 kilojoules per mole. In a dry thick-film electrode approximately 68 micrometers thick containing just 0.5 weight percent g-C3N4, the discharge capacity measured at a high discharge rate of 3C rose by 165.9 percent, from 58.8 to 156.2 milliampere-hours per gram. Power density increased by up to 2.85 times. In pouch-type full cells, capacity retention after 600 charge-discharge cycles improved from 72.9 percent for the additive-free electrode to 81.3 percent for the electrode containing the additive, indicating that the benefit extends beyond raw rate performance to long-term durability.

Just as important as the headline numbers is the team’s finding that more additive is not automatically better. Because g-C3N4 is a poor electrical conductor, adding excessive amounts raises the overall electrical resistance of the electrode, working against the very performance the additive is meant to improve. The researchers also observed the spring-back effect, in which a compressed dry electrode partially expands over time, making the internal ion-transport pathways more tortuous and partly undoing the gains in transport efficiency. Performance, they conclude, depends on the simultaneous design of three things: the amount of additive, its positioning within the electrode, and the pore structure of the electrode itself. They describe this combined approach as an architecture-interface co-design strategy, reflected in the title of the published paper.

The dry-electrode process itself carries commercial weight. Conventional wet processing requires large volumes of solvent, energy-intensive drying ovens, and systems for solvent recovery, all of which add cost, floor space, and energy consumption to a battery plant. Removing those steps raises prospects for commercial-scale production of high-energy batteries, particularly the high-capacity cells targeted at long-range electric vehicles, where every micron of extra active material and every gram of saved inactive component translates into driving range. The KRICT team is careful, however, to note the limits of the present study: it did not directly measure actual mass-production yields or reductions in manufacturing costs, so those economic benefits remain a prospect rather than a demonstrated result.

The study also illustrates how instrumentation partnerships support modern battery research. The collaboration included Thermo Fisher Scientific Korea, a global scientific instrumentation company, alongside the university partners, and the work was supported by KRICT’s institutional research program, the Nano and Material Technology Development Program through the National Research Foundation of Korea funded by the Ministry of Science and ICT, the Technology Innovation Program funded by the Ministry of Trade, Industry and Energy, and the Global TOP Strategic Research Group Program supported by the National Research Council of Science and Technology. Dr. Moon and Dr. Suk served as corresponding authors, with Hye Ji Eun, a post-master’s researcher, as first author; the KRICT team also included Dr. Jinkyu Park, a postdoctoral researcher, and student researcher Garam Lee.

For the battery industry, the message is twofold. First, dry-electrode manufacturing, already attractive for its cost and environmental profile, can be made compatible with thick, high-energy cathodes if ion transport inside the film is actively engineered rather than left to chance. Second, small quantities of a well-chosen additive, here only half a percent by weight, can produce outsized improvements in rate capability and cycling life when its chemistry and placement are matched to the electrode’s pore architecture. The transient lithium-nitrogen bonding mechanism offers a template that other nitrogen-rich porous materials might follow, and the demonstrated 56 percent reduction in charge-transfer activation energy gives researchers a concrete target for future additive design. As electric vehicle makers push for cells that store more energy in the same volume and weight, solutions that clear the lithium-ion traffic jam inside thick electrodes, without adding solvent back into the factory, are likely to attract close attention from cell developers worldwide.

Subject of Research: Dry-process thick-film lithium-ion battery cathodes enhanced with graphitic carbon nitride additives for faster ion transport

Article Title: KRICT clears lithium-ion traffic jams in thick electrodes for high-capacity batteries

Article References: KRICT clears lithium-ion traffic jams in thick electrodes for high-capacity batteries. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: lithium-ion batteries, dry electrode manufacturing, graphitic carbon nitride, cathode additives, thick-film electrodes, energy density, charge transfer, electrolyte wettability, electric vehicles, KRICT, battery cycle life, pouch cells