Long-Term High-Efficient Cus and Cu2s Cathodes for Lithium-Ion Batteries
CuS has been regarded as one promising cathode material via conversion reactions, featuring a theoretical capacity of 560 mAh/g, flat discharge plateaus, and good electrical conductivity. In spite of these advantages, CuS was reported with severe capacity fading 3. To circumvent this technical hurdle, Chung and Sohn 4 discovered that narrowing voltage window could help improve cycleability of CuS in LIBs, but CuS still could not sustain long-term high-efficient discharge-charge cycling. In comparison to CuS, there were even fewer studies reported on Cu2S. In this talk, we are going to present our recent progress on both CuS and Cu2S cathodes. We confirmed that a suitable selection on voltage windows is essential for securing reliable cycleability of the CuS and Cu2S cathodes. On the other hand, we found current collectors also have some effects on the LIB cathodes. To explore the underlying mechanism, we applied advanced synchrotron-based techniques of in situ X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) to track time-resolved structural changes of CuS and Cu2S during discharge-charge cycles. Based on all these efforts, we developed a set of conditions for achieving long-term high-efficient CuS (see figure 1) and Cu2S cathodes in LIBs. In addition, the electrochemical characteristics of CuS and Cu2S also will be comparatively discussed. This work is potentially significant for developing next-generation high-energy batteries for EVs.
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(3) Debart, A.; Dupont, L.; Patrice, R.; Tarascon, J. M. Solid State Sciences 2006, 8, 640.