Mechanically reinforced-CNT cathode for Li-O2 battery with enhanced specific energy via ex situ pore formation

Although Li-air batteries have been recognized as promising next-generation batteries for electric vehicles (EVs), there are still several issues in the development of practical cells that can achieve high specific energies for long driving ranges. In particular, it is important to employ a small amount of electrolyte and prevent it from escaping the cathode material during charging and discharging. Herein, a free-standing web-like mat cathode composed of mixed polymer nanofibers with high CNT loading is reported. High amounts of CNT (ca. 65.8 wt% of the polymer weight) is simultaneously loaded into the as-spun nanofibers with a mixed polymer matrix (consisting of polyacrylonitrile (PAN) and polyvinylpyrrolidone (PVP)). The domain occupied by PVP was converted into pores after a simple washing process, while the remaining PAN domain formed a backbone for the nanofibers. Using this cathode, a practical cell with a specific energy of 814 Wh/kg(-cell) is successfully developed by applying a controlled optimum ratio of electrolyte to CNT in the cathode. With these results, although still lacking, can provide handful insights and new directions towards development of future electrode materials as well as encourage to pursue strategies that requires minimal processing and activation steps while still achieving industrial acceptable performances.