Chao Lu, H. Wu, Yun Zhang
Dec 1, 2014
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Influential Citations
130
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Journal
Journal of Power Sources
Abstract
Abstract Cerium fluoride (CeF 3 ) coated lithium-rich layered Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 particles are synthesized using a facile chemical deposition route. The structural and electrochemical properties of pristine and CeF 3 -coated electrodes are investigated by X-ray diffraction (XRD), thermogravimetric-differential scanning calorimetry (TG-DSC), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), galvanostatic charge/discharge tests, electrochemical impedance spectra (EIS) and cyclic voltammetry (CV). The results indicate that the cathode particles are uniformly covered with a CeF 3 layer (∼10 nm thick) after 2 wt.% CeF 3 surface coating. The coated electrode shows an enhanced initial coulombic efficiency of 80.8% compared to 75.2% for the pristine electrode. Moreover, the coated electrode demonstrates better cyclic performance, which exhibits capacity retention of 91.7% after 50 cycles compared with only 82.1% for the pristine one. Furthermore, the CeF 3 -coated electrode delivers a superior high-rate capacity of 103.1 mAh g −1 at 5C, higher than 82.2 mAh g −1 for the pristine one. The remarkably improved cycling stability and high-rate capacity of the surface-modified electrode is ascribed to the presence of a stable and thin CeF 3 coating layer which effectively reduces the damage of electrode structure and suppresses the increase of impedance during cycling by preventing direct contact of electrode with electrolyte.