Polyaniline Nanocoating on the Surface of Layered Li[Li0.2Co0.1Mn0.7]O2 Nanodisks and Enhanced Cyclability as a Cathode Electrode for Rechargeable Lithium-I

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• 作者：Docheon Ahn ; Yang-Mo Koo ; Min Gyu Kim ; Namsoo Shin ; Jaehun Park ; Junho Eom ; Jaephil Cho ; Tae Joo Shin
• 刊名：Journal of Physical Chemistry C
• 出版年：2010
• 出版时间：March 4, 2010
• 年：2010
• 卷：114
• 期：8
• 页码：3675-3680
• 全文大小：263K
• 年卷期：v.114,no.8(March 4, 2010)
• ISSN：1932-7455

文摘

The surfaces of layer-structured Li[Li_0.2Co_0.1Mn_0.7]O₂ nanodisks were nanocoated with polyaniline and examined by SEM and TEM studies, via the chemical oxidative polymerization of aniline in an acid medium for 10 min—Mn⁴⁺ ions in the pristine lithium manganese oxides acted as oxidants. During this reaction, the crystal structure of the pristine nanodisks was retained, and the XRD patterns showed no evidence of H⁺ exchange with the Li⁺ located between the manganese oxide layers. The nanocoated polyaniline was in the low molecular weight of base states, and the majority (70%) was complexed with Li[Li_0.2Co_0.1Mn_0.7]O₂ nanodisks, as shown by UV−vis and FT-IR spectroscopic analysis. By application of nanocoated polyaniline nanodisks as the cathode material, the discharge capacity was improved by about 15%. Furthermore, the cyclability was enhanced with almost no change in discharge capacity being detected at extended cycle numbers, while that of pristine nanodisks showed a tendency to continually decrease as the number of cycles increased. Results from the present study suggest that a well-controlled polyaniline nanocoating, particularly formed with the aid of pristine metal oxides as oxidants for polymerization, can act as a potential buffer layer between electrodes and electrolytes, which makes this a promising method for the reducing/protection of continuous structural distortion that occurs during extended charge−discharge cycling.