In the field of green manufacturing, innovations in battery technology are crucial for advancing sustainable development. Recently, a Rice University research team achieved a breakthrough in lithium-ion battery research, offering new insights for improving the performance of thick battery electrodes.

Conventional wisdom held that creating channels in electrode materials through various patterning techniques could alleviate the issue of poor reaction uniformity in thick electrodes. However, a Rice University team led by materials scientist Ming Tang discovered that even when thick battery electrodes use structurally similar materials, differences in their internal chemistry significantly affect energy flow and performance—thermodynamic properties of electrode materials are more important than structural design.

Team member Zeyuan Li stated that "thick" battery electrodes can store more energy, beneficial for extending phone battery life or charging electric vehicles, but are limited by available capacity, making fast charging and discharging difficult and causing uneven reactions—like pouring water into a thick sponge, where water only penetrates part of it while the rest remains dry.

According to the study published in Advanced Materials, the researchers compared two common lithium-ion battery electrode materials: lithium iron phosphate (LFP) and nickel-manganese-cobalt oxide mixtures (NMC). Results showed that under identical cycling conditions, LFP electrodes degrade faster than NMC electrodes, experiencing more internal cracking and capacity loss due to imbalanced lithium flow.

Using high-resolution X-ray imaging technology at Brookhaven National Laboratory, the researchers tracked lithium ion movement inside the electrodes. They found strong reaction "hotspots" in LFP electrodes near the separator surface, with deeper regions largely inactive, and this nonuniformity persisted even after the battery rested; NMC electrodes exhibited a more balanced reaction profile.

Rice University Associate Professor of Materials Science and Nanoengineering Ming Tang stated that the thermodynamic properties of materials determine how reactions propagate, a discovery that brings new understanding to battery design and could improve the efficiency of thick electrodes.

Based on this finding, the research team developed a new metric called the "reaction homogeneity number," which captures structural and thermodynamic factors influencing reaction behavior, helping engineers evaluate how battery materials perform in thick electrodes. Tang noted that unevenly worn batteries fail faster and waste storage capacity; the new metric provides engineers with new guidance for selecting the right formulations in materials, microstructure, and geometry, helping improve thick electrode performance.