Perpendicularly aligned TiC-coated carbon cloth cathode for high-performance Li-O2 batteries

초록

To overcome the theoretical energy density limit of current lithium-ion batteries (LIBs), lithium-oxygen (Li-O2) batteries based on electrochemical formation and decomposition of lithium peroxide (Li2O2) have received much attention. However, critical cathode-related issues such as carbon decomposition, irreversible accumulation of Li2O2, and subsequent cathode passivation severely restrict the performance of Li-O2 batteries. To manage these issues, this paper reports a perpendicularly aligned TiC-coated carbon cloth (TiC-cloth) for Li-O2 battery cathodes prepared by a facile carbothermal method using easily available T-shirts as a substrate and growth of TiC on the outer surface. Coating with perpendicularly aligned TiC protects the carbon surface and increases the surface area to accommodate Li2O2. After verification of the successful coating, electrochemical tests of Li-O2 batteries were conducted, and the results were compared against TiC nanoparticle electrode casted manually onto carbonized T-shirts. The TiC-cloth affords enhanced oxygen reduction/evolution activity and cyclability for Li-O2 batteries compared with the TiC nanoparticles. Analyses demonstrate that this improvement arises from the reversible formation and decomposition of Li2O2 grown along the shape of the TiC on the carbonized T-shirts without carbon decomposition. The study reported here will be a keystone for the intelligent design of stable and efficient cathodes for Li-O2 batteries.

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