Electrical transport in Li₂SO₄-Li₂O-B₂O₃ glass-ceramic composites

372-375<span style="mso-bidi-font-weight: bold" lang="EN-GB">Lithium ion conducting glass-ceramic composites have been synthesized in Li2SO4-Li2O-B2O3 system by annealing the glass above its crystallization temperature. The electrical, structural and thermal characterization of these glass-ceramics reveals interesting results. The conductivity of the glass-ceramic increases with Li2SO4 content and exhibits a maximum of ~ 10<span style="font-family:Symbol;mso-ascii-font-family: " times="" new="" roman";mso-hansi-font-family:"times="" roman";mso-char-type:symbol;="" mso-symbol-font-family:symbol"="" lang="EN-GB">-4 at 200°C interestingly for a composition 1Li2SO4-99(0.67Li2O-0.33B2O3). The glass-ceramic samples are found to be thermally more stable than those of the glassy samples. </span

Structural and electrical transport studies in CuI substituted AgI-oxysalt glass-ceramic nanocomposites formed during crystallization

328-330Electrical transport in CuIxAgI1<span style="font-family: Symbol;mso-ascii-font-family:" times="" new="" roman";mso-hansi-font-family:"times="" roman";="" mso-char-type:symbol;mso-symbol-font-family:symbol"="" lang="EN-GB">-x-Ag2O-V2O5 glassy system has been studied for temperatures Tg ≤ T ≤ Tc. The XRD and DSC results suggest multiple crystallizations in this system. The electrical conductivity-temperature cycles are obtained for all the compositions and the conductivity behaviour for <i style="mso-bidi-font-style: normal">T ≥ Tc is explained using a crystallite by pass model. </span

Improving Interfaces in All-Solid-State Supercapacitors Using Polymer-Added Activated Carbon Electrodes

Solvent-free all-solid-state supercapacitors have recently received attention. Despite their highly specific capacitance, they suffer issues related to the solid–solid interface that degrade their performance during prolonged cycling. Here, we propose a novel strategy for improving the electrode–electrolyte interface by introducing a small amount of polymer into the activated carbon-based electrode. An electrode composition of 80AC:8SA:7AB:5[PEO0.95 (LiClO4)0.05]—where AC, SA, and AB stand for activated carbon, sodium alginate binder, and acetylene black, respectively—is optimized. A composite membrane—viz., PEO-LiClO4 reinforced with 38 wt% NASICON structured nano crystallites of Li1.3Al0.3Ti1.7(PO4)3—is used as a solid electrolyte. Incorporating a small amount of salt-in-polymer (95PEO-5 LiClO4) in the electrode matrix leads to a smooth interface formation, thereby improving the performance parameters of the all-solid-state supercapacitors (ASSCs). A typical supercapacitor with a polymer-incorporated electrode exhibits a specific capacitance of ~102 Fg−1 at a discharge current of 1.5 Ag−1 and an operating voltage of 2 V near room temperature. These ASSCs also exhibit relatively better galvanostatic charge–discharge cycling, coulombic efficiency, specific energy, and power in comparison to those based on conventional activated carbon

Neutron Scattering Studies of Lithium-Ion Diffusion in Ternary Phosphate Glasses

We have studied the diffusion mechanism of lithium ions in glassy oxide-based solid state electrolytes using elastic and quasielastic neutron scattering. Samples of xLi2SO4-(1-x)(Li2O-P2O5) were prepared using conventional melt techniques. Elastic and inelastic scattering measurements were performed using the triple-axis spectrometer (TRIAX) at Missouri University Research Reactor at University of Missouri and High Flux Backscattering Spectrometer (HFBS) at NIST Center for Neutron Research, respectively. These compounds have a base glass compound of P2O5 which is modified with Li2O. Addition of Li2SO4 leads to the modification of the structure and to an increase lithium ion (Li+) conduction. We find that an increase of Li2SO4 in the compounds leads to an increase in the Lorentzian width of the fit for the quasielastic data, which corresponds to an increase in Li+ diffusion until an over-saturation point is reached (\u3c 60% Li2SO4). We find that the hopping mechanism is best described by the vacancy mediated Chudley-Elliot model. A fundamental understanding of the diffusion process for these glassy compounds can help lead to the development of a highly efficient solid electrolyte and improve the viability of clean energy technologies

Neutron scattering studies of glassy solid state Li electrolytes

We present characterizations, performed using two different neutron scattering techniques, on superionic materials that are good candidates for use as solid state electrolytes in next generation Li+ ion batteries. The materials are glassy in nature and composed of a complex network of the following sub-units: Li2O, Li2SO4, and 2NH4H2PO2. This disordered structure is integral to its function in that it promotes Li+ ion conduction while suppressing electron conduction, the necessary qualities of a good Li+ electrolyte. We have implemented neutron diffraction to study the formation of crystallites upon heating of the material above 400∘ C. The crystallite formation is understood to be detrimental to the Li+ ion mobility and, hence, is identified with a diminished performance in devices that require heating in their fabrication process. We have also used a triple-axis spectrometer to begin to separate out the diffuse scattering that results from the disordered structure of the material from the diffuse scattering that results from dynamic processes that occur in it. This is done by a comparative study of the energy resolved versus energy integrated scattering over the full available q-range