High Performance TiP2O7 Based Intercalation Negative Electrode for Aqueous Lithium-Ion Batteries via a Facile Synthetic Route

• Published in: Journal of the Electrochemical Society 2015-01, Vol.162 (9), p.A1921-A1926
• Main Authors: Wu, Wei, Shanbhag, Sneha, Wise, Adam, Chang, Jiang, Rutt, Ann, Whitacre, Jay F.
• Format: Article
• Language: English
• ISSN: 0013-4651
• DOI: 10.1149/2.0071511jes

A composite TiP2O7/amorphous carbon material (C-TiP2O7) was prepared by an intensive mechanical mixing/solid-state synthesis method at 800°C. Physical properties were characterized via powder X-ray diffraction, Rietveld refinement, SEM, BET and TGA. Electrochemical performance was evaluated in both a three electrode test setup and two electrode coin cells via cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic cycling tests. The C-TiP2O7 composite demonstrated excellent cycling performance in 1 M Li2SO4 when matched with LiMn2O4 as a positive electrode: when cycled at C/2 for 150 cycles, the capacity retention is over 91% with coulombic efficiencies exceeding 99%. The initial discharge capacity obtained at a C/10 rate is 91 mAh/g which is about 75% of theoretical capacity 121 mAh/g. The apparent diffusion coefficient of C-TiP2O7 composite calculated from cyclic voltammetry result is 3.5*10−15 cm2/s.