The influence of different pre-treatments of current collectors and variation of the binders on the performance of Li4Ti5O12 anodes for lithium ion batteries

In order to optimize the electron transfer between the Li4Ti5O12-based active mass and the current collector, the surface of aluminum foil was modified either by alkaline etching or by a carbon coating. The as-modified aluminum foils were coated with an active mass of Li4Ti5O12 mixed with polyvinylidene fluoride, sodium carboxymethyl cellulose, or polyacrylic acid as binders. Untreated aluminum and copper foils served as reference current collectors. The corrosion reactions of aluminum foil with the applied binder solutions were studied and the electrode structure has been analyzed, depending on the binder. Finally, the electrochemical performance of the prepared electrodes was investigated. Based on these measurements, conclusions concerning the electrical contact between the different current collectors and the active masses were drawn. The energy density of the Li4Ti5O12 electrodes cast on carbon-coated aluminum foils was significantly increased, compared to the corresponding electrodes with a copper current collector

A novel molecular synthesis route to Li2S loaded carbon fibers for lithium-sulfur batteries

The synthesis of a novel air-stable molecular precursor (LiSC2H4)(2)NMe enables the formation of the desired 1D lithium sulfide (Li2S) via the electrospinning method under ambient conditions. The solubility of the precursor in polar solvents combined with a common polymer (PVP) allowed a suitable spinning solution to obtain ideal green Li2S loaded fibers. 3D fiber mats of the calcined homogeneous 1D electrospun Li2S/C fibers were characterized by electron microscopy and X-ray powder diffraction analysis. Direct integration of Li2S in an electronically conductive carbon matrix as the cathode obviates the need of elemental lithium as the anode, which is a great advantage against the reported lithium-sulfur batteries. An initial capacity of about 870 mA h g(-1) at C/20, a capacity retention of 73% after 100 cycles at C/10 and a capacity of about 400 mA h g(-1) at 1C were observed for the presented system