title: Nano-particle assembled porous core-shell ZnMn2O4microspheres with superb performance for lithium batteries.
abstract: Porous ZnMn2O4microspheres were prepared via a facile co-precipitation method followed by calcination at various temperatures and evaluated as anode materials for lithium ion batteries. The sample prepared at 600 °C outperformed the other samples in terms of electrochemical performance with high reversible capacity, high-rate capability, and excellent cycling performance. The capacity of the sample remained as high as 999 mAh g-1at a current rate of 100 mA g-1after 50 cycles-one of the best ever reported for ZnMn2O4-based materials. A high reversible capacity of 400 mAh g-1was retainable at a current density of 2000 mA g-1after 2500 cycles. A novel electrochemical reaction mechanism of ZnMn2O4anodes was established and investigated at length. The Mn3O4observed during the charge process was largely responsible for the enhanced performance, as confirmed by x-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The relatively large surface area, abundant porosity, large ion exchange space, and strong mechanical stability of the porous connected 3D framework were responsible for the unique oxidation/reduction Mn2+↔ Mn3+process we observed.
authors.affiliation: Key Laboratory of Physics and Technology for Advanced Batteries, Jilin University, Changchun 130012, People's Republic of China.
authors.forename: Tong
authors.initials: T
authors.lastname: Zhang
authors.forename: Huijuan
authors.initials: H
authors.lastname: Yue
authors.forename: Hailong
authors.initials: H
authors.lastname: Qiu
authors.forename: Yingjin
authors.initials: Y
authors.lastname: Wei
authors.forename: Chunzhong
authors.initials: C
authors.lastname: Wang
authors.forename: Gang
authors.initials: G
authors.lastname: Chen
authors.forename: Dong
authors.initials: D
authors.lastname: Zhang