The mechanism of the ionic conductivity enhancement in sulfur-doped Li _1.3 Al _0.3 Ti _1.7 (PO ₄ ) ₃ (LATP) solid electrolytes.

Different polymorphs of MnO₂ (α-, β-, and γ-) were produced by microwave hydrothermal synthesis, and graphene oxide (GO) nanosheets were prepared by oxidation of graphite using a modified Hummers’ method. Freestanding graphene/MnO₂ cathodes were manufactured through a vacuum filtration process. The structure of the graphene/MnO₂ nanocomposites was characterized using X-ray diffraction (XRD) and Raman spectroscopy. The surface and cross-sectional morphologies of freestanding cathodes were investigated by scanning electron microcopy (SEM). The charge–discharge profile of the cathodes was tested between 1.5 V and 4.5 V at a constant current of 0.1 mA cm⁻² using CR2016 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.

Freestanding multiwalled carbon nanotube and titanium (IV) oxide anode paper was prepared by vacuum filtration of multiwall carbon nanotubes/TiO₂ hybrid material, which was synthesized by the radio frequency magnetron sputtering techniques. Field emission scanning electron microscopy images revealed that the carbon nanotubes (CNTs) form a three-dimensional nanoporous network, in which ultrafine TiO₂ crystals that had crystallite sizes ranging between 7.14 nm and 12.21 nm were distributed homogenously over the surfaces of multiwalled CNT bundles. Electrochemical measurements demonstrated that the prepared powder by using 200 W radio frequency power had excellent cyclic retention, with the high specific capacity of 230 rnAh g^−l up to 50 cycles at a current density. Freestanding papers composed of multiwall carbon nanotubes could act as a flexible mechanical support for strain release offering an efficient electrically conducting channel ,whereas the TiO₂ provides the high capacity. The electrochemical response is maintained in the initial and further cycling process. Such capabilities demonstrate that this model hold great promise for applications requiring flexible and bendable Li-ion batteries. Copyright © 2014 John Wiley & Sons, Ltd.