MnO₂ Nano-Rods Prepared by Redox Reaction as Cathodes in Lithium Batteries

Abstract

We report the structural and electrochemical of the α- and β-MnO2 phases synthesized by redox reaction of ammonium persulphate with manganese sulphate and manganese nitrate. A single phase of α-MnO2 was observed or the sample prepared from manganese sulphate, while β-MnO2 phase was obtained from manganese nitrate. Characteristic bands of hollandite and rutile phase were observed by FTIR. Nanorods structures were observed by images of transmission electron microscopy for both samples. Good electrochemical performance was observed for β-MnO2, which yields a specific discharge capacity of 180 and 130 mAh g− 1 in the first and 45th cycle respectively. The specific discharge capacity of α-MnO2 is ca. 210 mAh g− 1 at first cycle that decreases to 115 mAh g− 1 in the 45th cycle.

Nanostructured MnO2 as Electrode Materials for Energy Storage

“…The as-synthesized amorphous MnO 2 converts into crystalline α -form upon annealing at temperatures <400 °C. Hashem et al synthesized two polymorph MnO 2 nanorods using redox reaction between (NH 4 ) 2 S 2 O 8 and MnSO 4 ·4H 2 O for α -MnO 2 and (NH 4 ) 2 S 2 O 8 and Mn(NO 3 ) 2 ·4H 2 O for β -MnO 2 [51]. Rod-shaped structures of α -MnO 2 and β -MnO 2 are shown in Figure 6.…”

Electrochemical performance of nanosized MnO2 synthesized by redox route using biological reducing agents

“…Numerous methods to synthesize MnO2 include sol-gel [22], hydrothermal methods [23][24][25], refluxing method [26] and wet-chemical methods [27][28][29][30][31]. For most of them, strong mixing, long time and high temperature are required, resulting in the waste of a lot of energy [32,33]. It is then desirable to develop facile, cheap, environmentally benign, and size control routes to prepare MnO2 nanoparticles [34].…”

Nanotechnology for Energy Storage

“…HTS offers other advantages over conventional ceramic methods. All forms of nanoscale materials can be prepared, namely nanopowders [51], nanofibers [52], nanobelts [53], nanoplates [54], nanowires [55], nanorods [56], nanovesicles [57], etc. The use of inexpensive, environmentally benign water as a solvent offers a "green" manufacturing approach for large-scale production of Li(Fe,Mn)PO 4 /C cathodes for high-power hybrid electric vehicle and plug-in hybrid electric vehicle applications.…”