solid-state-graft-copolymer-electrolytes-for-lithium-battery

Solid-state Graft Copolymer Electrolytes for Lithium Battery Applications

Battery safety has been a very important research area over the past decade. Commercially available lithium ion batteries employ low flash point (&lt;80 ...

Massachusetts Institute of Technology

Using the layer-by-layer (LbL) assembly technique, we create a polymer-clay structure from a unique combination of LbL materials: poly(ethylene imine), Laponite clay, and poly(ethylene oxide). This trilayer LbL structure is assembled using a combination of hydrogen bonding and electrostatic interactions. The films were characterized using ellipsometry, profilometry, X-ray photon spectroscopy, atomic force microscopy, scanning electron microscopy, wide-angle X-ray diffraction, grazing-incidence small-angle X-ray scattering, and electrochemical impedance spectroscopy (EIS). We observe a layered, anisotropic structure, which resulted in in-plane ion transport 100 times faster than cross-plane at 0% relative humidity. This study represents a first application of EIS in determining anisotropic ion transport in LbL assemblies and its correlation to structural anisotropy.

Anisotropic structure and transport in self-assembled layered polymer-clay nanocomposites.

The electrochemical behavior of ZnTe and CdTe compound semiconductors dissolved in molten ZnCl(2) and equimolar CdCl(2)-KCl, respectively, was examined. In these melts dissolved Te is present as the divalent telluride anion, Te(2-), which was found able to be converted to elemental metal by electrochemical oxidation at the anode. ZnTe-ZnCl(2) melts were studied at 500 Â°C by standard electrochemical techniques. On the basis of these results, electrolysis was performed, resulting in the simultaneous extraction of phase-pure liquid Zn at the cathode and phase-pure liquid Te at the anode. This new process, involving the simultaneous deposition of liquid metals at electrodes of opposite polarity, is termed herein as ambipolar electrolysis. A melt consisting of CdTe dissolved in equimolar CdCl(2)-KCl was processed by ambipolar electrolysis, resulting in the production of liquid Cd at the cathode and liquid Te at the anode. Ambipolar electrolysis could enable new approaches to recycling compound semiconductors and semiconductor devices, such as CdTe solar cells.

Recycling ZnTe, CdTe, and other compound semiconductors by ambipolar electrolysis.

Batteries are an attractive option for grid-scale energy storage applications because of their small footprint and flexible siting. A high-temperature (700 Â°C) magnesium-antimony (Mg||Sb) liquid metal battery comprising a negative electrode of Mg, a molten salt electrolyte (MgCl(2)-KCl-NaCl), and a positive electrode of Sb is proposed and characterized. Because of the immiscibility of the contiguous salt and metal phases, they stratify by density into three distinct layers. Cells were cycled at rates ranging from 50 to 200 mA/cm(2) and demonstrated up to 69% DC-DC energy efficiency. The self-segregating nature of the battery components and the use of low-cost materials results in a promising technology for stationary energy storage applications.

Magnesium-antimony liquid metal battery for stationary energy storage.

Liquid metal batteries: past, present, and future.

Batteries m&eacute;tal liquides : pass&eacute;, pr&eacute;sent et avenir.

Batterie metalliche liquide: passato, presente e futuro.

The thermodynamic properties of multiple liquid alloys with strong negative deviation from ideality were successfully modeled by the molecular interaction volume model (MIVM). The modeled partial Gibbs free energy of calcium in Ca-Ag, Ca-In, Ca-Pb, Ca-Sn, Ca-Tl, and Ca-Zn at 800 Â°C was within 1.5 kJ/mol of the existing experimental data. The partial Gibbs free energy of calcium in Ca-Bi liquid alloys at 600 Â°C was predicted within 1.6 kJ/mol (or 1%) by the MIVM from experimental data at 800 Â°C. For the first time, the MIVM was applied to a ternary system far from ideality, Ca-Sb-Pb. The partial Gibbs free energy of Ca in six Ca-Pb-Sb alloys was determined by emf measurements in a cell configured as Ca(s)|CaF2(s)|Ca-Sb-Pb, over the temperature range of 500-830 Â°C. These values were 2% (or 5 kJ/mol) more negative than those predicted by the MIVM using experimental data for the Ca-Pb, Ca-Sb, and Pb-Sb binary alloys. This difference was attributed to the inability of the MIVM to account for interactions between the first nearest neighbors of Ca, Pb and Sb in the ternary Ca-Sb-Pb alloy.

Application of the Molecular Interaction Volume Model (MIVM) to Calcium-Based Liquid Alloys of Systems Forming High-Melting Intermetallics.

Molten oxide electrolysis (MOE) is an electrometallurgical technique that enables the direct production of metal in the liquid state from oxide feedstock, and compared with traditional methods of extractive metallurgy offers both a substantial simplification of the process and a significant reduction in energy consumption. MOE is also considered a promising route for mitigation of CO2 emissions in steelmaking, production of metals free of carbon, and generation of oxygen for extra-terrestrial exploration. Until now, MOE has been demonstrated using anode materials that are consumable (graphite for use with ferro-alloys and titanium) or unaffordable for terrestrial applications (iridium for use with iron). To enable metal production without process carbon, MOE requires an anode material that resists depletion while sustaining oxygen evolution. The challenges for iron production are threefold. First, the process temperature is in excess of 1,538 degrees Celsius (ref. 10). Second, under anodic polarization most metals inevitably corrode in such conditions. Third, iron oxide undergoes spontaneous reduction on contact with most refractory metals and even carbon. Here we show that anodes comprising chromium-based alloys exhibit limited consumption during iron extraction and oxygen evolution by MOE. The anode stability is due to the formation of an electronically conductive solid solution of chromium(iii) and aluminium oxides in the corundum structure. These findings make practicable larger-scale evaluation of MOE for the production of steel, and potentially provide a key material component enabling mitigation of greenhouse-gas emissions while producing metal of superior metallurgical quality.

Donald R. Sadoway

Materials Science and Engineering

Massachusetts Institute of Technology

Solid-state Graft Copolymer Electrolytes for Lithium Battery Applications

Donald R. Sadoway

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Materials Science and Engineering

Massachusetts Institute of Technology

Solid-state Graft Copolymer Electrolytes for Lithium Battery Applications

Materials Science and Engineering