Effect of the secondary rutile phase in single-step synthesized carbon-coated anatase TiO2 nanoparticles as Lithium-ion anode material

TiO2 has been investigated as an alternative anode material candidate for lithium-ion batteries for several years now due to its advantageous safety and rate capability in combination with its nontoxicity and abundance. Herein, the synthesis via laser pyrolysis is reported, which allows the single-step, industrial-scale realization of carbon-coated TiO2 nanoparticles. The modification of the synthesis parameters enables the variation of the rutile-to-anatase phase ratio. Following comprehensive physicochemical and electrochemical characterization, both the higher and lower rutile-to-anatase ratios show very stable cycling in lithium battery half cells, whereas the extended presence of the rutile phase limits the achievable specific capacity and lowers the apparent lithium-ion diffusion coefficient, which leads to relatively lower capacities at elevated current densities. © 2021 The Authors. Energy Technology published by Wiley-VCH GmbH