44-0141, a = 9.7847, c = 2.863). The cell volume of caddice-clew-like MnO2 is 273.97 Å3 which is also highly identical to the standard

values (274.1 Å3),while the lattice parameters of urchin-like MnO2 are a = 9.8084 and c = 2.8483. According to the standard values, the crystal cell expands in a and b directions and contracts in c direction. The cell volume of urchin-like MnO2 is 274.02 Å3. The average size of the caddice-clew-like MnO2 crystal grains is calculated to be 32 nm according to the Scherrer equation D = Kλ/βcosθ using the strongest diffraction peak of (211) [D is crystal grain size (nm), K is the Scherrer constant (0.89), λ is the X-ray selleck chemical wavelength (0.154056 nm) for Cu Kα, β is the full width at half maximum (FWHM) of the peak (211), and θ is the angle of diffraction peak],while the measured diameter of caddice-clew-like MnO2 is 53 nm. The average size of the urchin-like MnO2 crystal grains is calculated to be 51 nm according to the Scherrer www.selleckchem.com/products/Cyt387.html equation. The measured diameter of the short nanorods on urchin-like MnO2 is about 50 nm. As can be seen, the calculated crystallite size value of caddice-clew-like MnO2 crystal is a little smaller than the measured

value, but the calculated crystallite size value of urchin-like MnO2 crystal is identical. Although the MnO2 micromaterials are in micrometer scale, they are confirmed to assemble by nanomaterials. Consequently, although the two MnO2 micromaterials are with identical crystal structure, they may have some difference in the electrochemical Selleck Fedratinib GPX6 performance as the urchin-like MnO2 has the expanded lattice parameters. Figure 3 The XRD patterns of MnO 2 materials. (a) Caddice-clew-like and (b) urchin-like MnO2 samples. Electrochemical performance Figure 4 presents the typical charge-discharge voltage curves

of the anodes (compared to the full battery) constructed from MnO2 micromaterials at 0.2 C rate in the voltage range of 0.01 to 3.60 V (vs. Li/Li+). For clarity, only selected cycles are shown. As shown, the two α-MnO2 micromaterials both have high initial discharge specific capacity as approximately 1,400 mAh g−1, while the theoretical discharge specific capacity is 1,232 mAh g−1. The extra discharge specific capacities of the as-prepared MnO2 micromaterials may result from the formation of solid electrolyte interface (SEI) layer which is known as a gel-like layer, containing ethylene oxide-based oligomers, LiF, Li2CO3, and lithium alkyl carbonate (ROCO2Li), during the first discharging process [29]. The discharge specific capacities of the as-prepared MnO2 micromaterials in the second cycle are 500 mAh g−1(caddice-clew-like MnO2) and 600 mAh g−1 (urchin-like MnO2), respectively. There is an attenuation compared to the initial discharge capacity. After the fifth cycling, the discharge specific capacities of the as-prepared MnO2 micromaterials are 356 mAh g−1 (caddice-clew-like MnO2) and 465 mAh g−1 (urchin-like MnO2), respectively.