Lawrence Berkeley National Laboratory

Microsized single-crystal Li1.08Mn1.89Al 0.03O4 (LAMO) was synthesized via polyvinylpyrrolidone (PVP) combustion method. X-ray diffraction (XRD), scanning electron microscope (SEM) and high-resolution transmission electron microscopy (HRTEM) characterization results indicate that the as-prepared LAMO has good crystallinity, uniform and smooth-surfaced morphology, and very low specific surface area. Galvanostatic charge-discharge tests demonstrate its excellent electrochemical performance. The capacity retentions at 30°C and 55°C are 98.8% and 93.3% respectively after 200 cycles at 1 C charge/discharge rate. Moreover, the LAMO exhibits excellent rate and low temperature performance. Even at high rates of 40 C and 60 C, the as-prepared LAMO are still able to deliver 91.2% and 85.6% capacity relative to the discharge capacity at C/5. The specific discharge capacity at -20°C is 97.9 mAh g-1 which is 93.7% of the capacity discharging at 25°C. To study the reason of the excellent rate performance, the potential intermittent titration technique (PITT) tests and cyclic voltammetry (CV) measurements were conducted and the lithium chemical diffusion coefficient (DLi+) was calculated. © Published by Elsevier B.V.