Dendrite-Free Lithium Anodes with a Metal Organic Framework-Derived Cake-like TiO2 Coating on the Separator

Lithium metal, with a high theoretical capacity of 3860 mAh/g and a low electrochemical potential of -3.040 V, is an attractive anode material. However, its application has been hampered by irregular lithium dendrite growth and low coulombic efficiency. To solve these problems, a facile air calcination strategy was used to prepare cake-like TiO2 nanoparticles with rich pores, which were further coated on one side of the commercial Celgard separator. The nanoscale mesoporous channels on the surface of TiO2 particles can effectively block the growth of lithium dendrites, leading to dense and uniform Li deposition with a high coulombic efficiency. Compared with the blank cell (50 cycles of normal operation), the Li||Cu cell with modified separator can run 100 cycles at 2 mA/cm(2) with an average coulombic efficiency of 97.3 %. These results herald a new approach to dendrite-free lithium anodes by nanostructured ceramic coating on the separator.