The effect of Al(OH)3 coating on the Li[Li0.2Ni0.2Mn0.6]O2 cathode material for lithium secondary battery

• Published in: Electrochimica acta 2005-08, Vol.50 (24), p.4784-4791
• Main Authors: KANG, Y.-J, KIM, J.-H, LEE, S.-W, SUN, Y.-K
• Format: Article
• Language: English
• Subjects: Applied sciences; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Exact sciences and technology
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2005.02.032

Layered Li[Li0.2Ni0.2Mn0.6]O2 powder was modified by coating its surface with amorphous Al(OH)3. Energy dispersive spectroscopy (EDS) showed that nano-sized Al(OH)3 powders were homogeneously dispersed in the parent Li[Li0.2Ni0.2Mn0.6]O2 powders. Al(OH)3 coated Li[Li0.2Ni0.2Mn0.6]O2 exhibited an greater retention capacity at higher rates compared to uncoated Li[Li0.2Ni0.2Mn0.6]O2. The low area specific impedance (ASI) value of the Al(OH)3 is the major factor for its higher rate performance. The 1.4 wt.% Al(OH)3 coated sample had an impedance of 41 Omegacm2 while uncoated Li[Li0.2Ni0.2Mn0.6]O2 had a 57 Omegacm2 at 30-80% state of charge. Electrochemical impedance spectroscopy (EIS) also showed that the Al(OH)3 coated sample had a lower charge transfer resistance (Rct) than the uncoated sample. Differential scanning calorimetry (DSC) analysis showed that Al(OH)3 coating improved the thermal stability. Al(OH)3 coating increased the onset temperature of thermal decomposition and reduced the amount of heat for the exothermic peak.