Freestanding graphene/MnO₂ cathodes for Li-ion batteries

• Şeyma Özcan,
• Aslıhan Güler,
• Tugrul Cetinkaya,
• Mehmet O. Guler and
• Hatem Akbulut

Beilstein J. Nanotechnol. 2017, 8, 1932–1938, doi:10.3762/bjnano.8.193

• coin cells. The initial specific capacity of graphene/α-, β-, and γ-MnO2 freestanding cathodes was found to be 321 mAhg−1, 198 mAhg−1, and 251 mAhg−1, respectively. Finally, the graphene/α-MnO2 cathode displayed the best cycling performance due to the low charge transfer resistance and higher

• electrochemical reaction behavior. Graphene/α-MnO2 freestanding cathodes exhibited a specific capacity of 229 mAhg−1 after 200 cycles with 72% capacity retention. Keywords: CR2016 coin cells; freestanding cathode; graphene; Li-ion battery; MnO2; Introduction Nowadays low cost, clean and sustainable energy

• The α-, β-, and γ-MnO2 phases were synthesized by a microwave-assisted hydrothermal method. α-MnO2 nanowires and β-MnO2 nanorods were prepared according to our previous report [8]. To prepare γ-MnO2, 1.83 mg of (NH4)2S2O8, 1.35 mg of MnSO4 and 3 mmol were dissolved in 80 mL of distilled water. Then

Structural properties and thermal stability of cobalt- and chromium-doped α-MnO₂ nanorods

• Romana Cerc Korošec,
• Polona Umek,
• Alexandre Gloter,
• Jana Padežnik Gomilšek and
• Peter Bukovec

Beilstein J. Nanotechnol. 2017, 8, 1032–1042, doi:10.3762/bjnano.8.104

• Solides, Université Paris Sud, CNRS UMR 8502, F-91405 Orsay, France Faculty of Mechanical Engineering, University of Maribor, Smetanova 17, SI-2000 Maribor, Slovenia 10.3762/bjnano.8.104 Abstract α-MnO2 nanorods were synthesized via the hydrothermal decomposition of KMnO4 in an acidic environment in the

• synthesized at 170 °C is significantly lower than in the undoped samples. Analysis of an individual cobalt-doped α-MnO2 nanorod with HAADF-STEM reveals that the distribution of cobalt through the cross-section of the nanorod is uniform. The course of thermal decomposition of the doped nanorods is similar to

• that of the undoped ones. Dopant ions do not preserve the MnO2 phase at higher temperatures nor do they destabilize the cryptomelane structure. Keywords: α-MnO2; doping; EXAFS; nanorods; XANES; Introduction The wide range of physical and chemical properties of manganese dioxide (MnO2), which exists

From lithium to sodium: cell chemistry of room temperature sodium–air and sodium–sulfur batteries

• Philipp Adelhelm,
• Pascal Hartmann,
• Conrad L. Bender,
• Martin Busche,
• Christine Eufinger and
• Juergen Janek

Beilstein J. Nanotechnol. 2015, 6, 1016–1055, doi:10.3762/bjnano.6.105

• capacities as high as 3000 mAh/gcarbon by introducing α-MnO2 nanowires as catalyst in the oxygen cathode [31]. From 2008 onwards, the number of publications on Li/O2 batteries rapidly increased. The progress in Li/O2 research and development is the subject of numerous review articles [22][32][33][34

Magnesium batteries: Current state of the art, issues and future perspectives

• Rana Mohtadi and
• Fuminori Mizuno

Beilstein J. Nanotechnol. 2014, 5, 1291–1311, doi:10.3762/bjnano.5.143