Synthesis of Li[Ni0.2Li0.2Mn0.6]O2 nano-particles and their surface modification using a polydopamine layer

• Published in: Journal of power sources 2013-12, Vol.244, p.222-233
• Main Authors: Lee, Hye Jin, Park, Yong Joon
• Format: Article
• Language: English
• Subjects: Applied sciences; Cathode; 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; Lithium battery; Materials; Nano-particle; Polydopamine; Surface coating
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2013.01.154

Li[Ni0.2Li0.2Mn0.6]O2 nanoparticles are fabricated using a combustion method in which three different dispersing agents, gelatin, urea and Pluronic® P-123 (P123), are introduced as dispersing agents. The dispersing agents are used in order to disperse the primary particles during the sol–gel thermolysis process and reduce the sizes of the powder particles. Reducing the size of the particles is effective in improving the rate capability of the Li[Ni0.2Li0.2Mn0.6]O2 electrode. However, the cyclic performance deteriorates due to vigorous side reactions with the electrolyte. In order to avoid this, the surfaces of the Li[Ni0.2Li0.2Mn0.6]O2 nanoparticles, prepared using dispersing agents, are modified by a ZrO2 surface coating. A novel precoating of polydopamine is used to aid the ZrO2 coating of the nanosized particles. The surfaces of the coated Li[Ni0.2Li0.2Mn0.6]O2 particles are homogeneously covered with the ZrO2, demonstrating the effectiveness of the polydopamine precoating as a binding agent between the nanosized cathodic particles and the coating material. The cyclic performance and thermal stability of the coated Li[Ni0.2Li0.2Mn0.6]O2 nanoparticles are significantly enhanced, showing that the ZrO2 coating layer successfully protected the nanoparticles from the reactive electrolyte. ► Polydopamine was successfully used as a binding agent for coating of cathode. ► The high reactivity of the polydopamine layer aided adhesion with the ZrO2 coating. ► It also helped in its homogeneous dispersion of coating material. ► The ZrO2 coating suppressed side reactions with the electrolyte. ► And protected the surface of Li[Ni0.2Li0.2Mn0.6]O2-based cathode.