Controllable synthesis of hollow bipyramid β-MnO(2) and its high electrochemical performance for lithium storage.
Three types of MnO2 nanostructures, viz., α-MnO2 nanotubes, hollow β-MnO2 bipyramids, and solid β-MnO2 bipyramids, have been synthesized via a simple template-free hydrothermal method. Cyclic voltammetry and galvanostatic charge/discharge measurements demonstrate that the hollow β-MnO2 bipyramids exhibit the highest specific capacity and the best cyclability; the capacity retains 213 mAh g(-1) at a current density of 100 mA g(-1) after 150 cycles. XRD patterns of the lithiated β-MnO2 electrodes clearly show the expansion of lattice volume caused by lithiation, but the structure keeps stable during lithium insertion/extraction process. We suggest that the excellent performance for β-MnO2 can be attributed to its unique electrochemical reaction, compact tunnel-structure and hollow architecture. The hollow architecture can accommodate the volume change during charge/discharge process and improve effective diffusion paths for both lithium ions and electrons.
State Key Laboratory of Material Processing and Die and Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology , Wuhan, Hubei 430074, China.
Wei-Min
WM
Chen
Long
L
Qie
Qing-Guo
QG
Shao
Li-Xia
LX
Yuan
Wu-Xing
WX
Zhang
Yun-Hui
YH
Huang
D011211:Electric Power Supplies; D055664:Electrochemical Techniques; D004566:Electrodes; D007477:Ions / Q000737:chemistry; D008094:Lithium / Q000737:chemistry*; D017895:Manganese Compounds / Q000737:chemistry*; D043942:Nanotubes / Q000737:chemistry; D010087:Oxides / Q000737:chemistry*
D007477:Ions; D017895:Manganese Compounds; D010087:Oxides; C027424:manganese oxide; D008094:Lithium