Thicker electrodes mean higher energy storage potential, as lithium ions are able to cover more area, the researchers explained. Flat layers of conventional electrode material force lithium ions to bend back and forth as they come in and out, ultimately slowing down charging.
They further noted that this work aims to seek high-power energy storage systems that could be used in future electric vehicles. However, using very fine stacks of two-dimensional materials to make electrodes for batteries has certain limitations.
Guihua Yu, an author of the research paper, said, “Two-dimensional materials are generally regarded as potential candidates for high-speed energy storage applications on the grounds that they can transport charges rapidly with only a few nanometers thick. For next-generation high-performance batteries with electrode design, the re-stacking of nanosheets could lead to a significant bottleneck in charge transport, making it difficult to combine high-energy and fast charging.”
With this in mind, scientists have come up with a new way to combine thin layers of electrode material in order to achieve high energy and fast charging. Specifically, they used a magnetic field to carefully manipulate the orientation of these thin layers, stacking them in a vertical, rather than conventional, way. This creates a “high-quality path” that allows lithium ions to pass more efficiently.
Zhengyu Ju, co-author of the study, added, “This electrode exhibits excellent electrochemical performance, in part due to the newly designed unique architecture with high mechanical strength, high electrical conductivity, and properties that facilitate lithium ion transport.”
It is reported that the performance of the electrodes created by the team far exceeds that of electrodes that have been commercialized. Compared with the control group with horizontally stacked electrode layers, the vertical stacking scheme was able to fill 50% of the battery capacity in 30 minutes, much faster than the former’s 2 hours and 30 minutes. The research was recently published in the Proceedings of the National Academy of Sciences (PNAS).
Although the R&D is still in the early stages, the researchers cite test results that its thick electrodes provide the best capacity reference data reported in the literature so far, and they firmly believe that its technical route has the potential to allow EVs to last as long as commercially available products. double. However, there is still a lot of work to be done to achieve this goal.
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