Identification of reversible insertion-type lithium storage reaction of manganese oxide with long cycle lifespan

• 作者: Yuxuan Zhang Fang Lian Jianhao Lu Laijun Ma Ning Chen Yanan Chen Dingguo Xia
• 来源期刊: 能源化学
• 年，卷（期）: 2020,（7）
• 页码范围: 144-151
• 页数: 8页
• 语种: 英文

摘要

Recently, MnO2 has gained attention as an electrode material because of its very high theoretical capacity and abundant availability. However, the very high volumetric change caused by its conversion-type reac-tion results in bad reversibility of charge-discharge. In this study, δ-MnO2 of thickness 8 nm anchored on the surface of carbon nanotubes (CNT) by Mn-O-C chemical bonding is synthesized via a facile hy-drothermal method. Numerous ex-situ characterizations of the lithium storage process were performed. Furthermore, density functional theory (DFT) calculations indicated thatδ-MnO2 (012) thermodynami-cally prefers bonding with CNTs. Moreover, the interfacial interaction reinforces the connection of Mn-O and reduces the bond strength of Li-O in lithiated MnO2, which could facilitate an intercalation-type lithium storage reaction. Consequently, the as-synthesizedδ-MnO2 retains an excellent reversible capac-ity of 577.5 mAh g- 1 in 1000 cycles at a high rate of 2 A g- 1 between 0.1 V and 3.0 V. The results of this study demonstrate the possibility of employing the cost-effective transition metal oxides as intercalation lithium storage dominant electrodes for advanced rechargeable batteries.