2018 Volume 26 Pages 46-52
We prepared Na-ion battery anodes of Nb-doped rutile TiO2 and indium phosphide (InP) without conductive additive and binder by using an aerosol process in which active material powders are sprayed onto current collector substrates and are strongly adhered to form film electrodes. In the evaluation for the electrode comprised of Nb-doped TiO2 synthesized by a hydrothermal method, a better charge-discharge performance was obtained for Nb-doped TiO2 with a higher ratio of crystallite size to particle size. Among various binary phosphide electrodes, the InP anode showed a good performance next to an Sn4P3 anode which has been developed by the authors. The nanostructure analysis of the electrode active material suggests that the phase separation of InP occurred during its sodiation to form elemental In and P, and that InP anode showed good performance because metallic In phase relaxed a stress from P phase and compensated a poor electronic conductivity of Na3P phase.