Electrochemical Property of Particle-size Controlled H₂Ti₁₂O₂₅ as a Negative Electrode Material for Lithium-ion Battery

Abstract

We have successfully prepared the particle-size controlled H₂Ti₁₂O₂₅ by soft chemical synthetic technique using the ball-milled and annealed Na₂Ti₃O₇ as a starting compound. In this synthetic route, we first prepared the particle-size controlled Na₂Ti₃O₇ by ball-milling and subsequent annealing at 873–1073 K. Then, H₂Ti₃O₇ was prepared by Na⁺/H⁺ ion-exchange reaction using HCl solution, and H₂Ti₁₂O₂₅ was synthesized by heating H₂Ti₃O₇ at 533 K. The initial discharge capacity of the H₂Ti₁₂O₂₅ sample thus obtained was achieved to be 255 mAh g⁻¹, which was higher than those previously reported for H₂Ti₁₂O₂₅ samples, while initial irreversible capacity also increased together with the amounts of smaller particles.