In this work, a series of Li-rich layered metal oxides (LLMO) as cathode materials for lithium ion batteries were prepared by the coprecipitation method. Various surfactants were introduced into the preparation of Al2O3-modified LLMO. The roles of surfactants were systematically investigated to reveal the mechanism of Al2O3 modification. The microstructure, morphology and electrochemical performance of the as-prepared samples were studied by the X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), galvanostatic discharge/charge measurement, cycling stability, rate capability and electrochemical impedance spectroscopies. The experimental results showed that Al2O3 nanoparticles were uniformly dispersed on the surface of LLMO by using N, N, N-trimethyl-1-dodecanaminium bromide (DTAB) as the surfactant. Al2O3-modified LLMO used DTAB as surfactant delivered the initial discharge capacity of 186 mAh·g-1 at the current density of 600 mA·g-1. After 500 cycles, the reversible discharge capacity was 132 mAh·g-1 with a satisfactory capacity retention of 71%. Moreover, the voltage fade of LLMO was greatly suppressed after Al2O3 modification, which exhibited superior electrochemical performances.
Received: 02 December 2016
Published: 22 February 2017
Fund: the National Natural Science Foundation of China(21403196);the National Natural Science Foundation of China(51572240);the National Natural Science Foundation of China(51677170);Natural Science Foundation of Zhejiang Province, China(LY15B030003);Natural Science Foundation of Zhejiang Province, China(LY16E070004);Natural Science Foundation of Zhejiang Province, China(LY17E020010);Ford University Research Program, China