Free-standing N,Co-codoped TiO2 nanoparticles for LiO2-based Li–O2 batteries

Abstract

Li–O₂ batteries based on lithium superoxide (LiO₂) would address the issues of significant polarization, low energy density and inferior cycle performance. However, LiO₂ as an intermediate product in the discharge process is very active and could be readily disproportionated into Li₂O₂. Thus, it is challenging to find an appropriate cathode catalyst, which can stabilize the active discharge product LiO₂. In this work, heteroatom N and Co codoped titanium dioxide nanoparticles grown on carbon fibers (N,Co-TiO₂/CFs) are fabricated and employed as a non-noble metal cathode catalyst for Li–O₂ batteries. LiO₂ formed in the Li–O₂ batteries can be repeatedly charged and discharged with a very low charge potential of approximately 3.0 V (vs. Li/Li⁺). N,Co-codoped TiO₂ is proposed to be responsible for the generation of stable LiO₂. This discovery opens a new way for the fabrication of non-noble metal cathode catalysts for high-performance LiO₂-based Li–O₂ batteries.