Designing Spinel Li₄Ti₅O₁₂ Electrode as Anode Material for Poly(ethylene)oxide-Based Solid-State Batteries

The development of a promising Li metal solid-state battery (SSB) is currently hindered by the instability of Li metal during electrodeposition; which is the main cause of dendrite growth and cell failure at elevated currents. The replacement of Li metal anode by spinel Li4Ti5O12 (LTO) in SSBs would avoid such problems, endowing the battery with its excellent features such as long cycling performance, high safety and easy fabrication. In the present work, we provide an evaluation of the electrochemical properties of poly(ethylene)oxide (PEO)-based solid-state batteries using LTO as the active material. Electrode laminates have been developed and optimized using electronic conductive additives with different morphologies such as carbon black and multiwalled carbon nanotubes. The electrochemical performance of the electrodes was assessed on half-cells using a PEO-based solid electrolyte and a lithium metal anode. The optimized electrodes displayed an enhanced capability rate, delivering 150 mAh g−1 at C/2, and a stable lifespan over 140 cycles at C/20 with a capacity retention of 83%. Moreover, postmortem characterization did not evidence any morphological degradation of the components after ageing, highlighting the long-cycling feature of the LTO electrodes. The present results bring out the opportunity to build high-performance solid-state batteries using LTO as anode material

Spin-flip Raman spectroscopy of ZnCdSe-based heterostructures

This thesis presents the results of the study of ZnCdSe-based heterostructures of two systems, namely bulk single-phase cubic ZnCdSe epilayers with Cd content varying from 0 to 100 percent and ZnCdSe/Zn(S)Se quantum wells. In the latter system increased attention has been paid to the special case of submonolayer structures. The main tool of the study, spin-flip Raman spectroscopy, enabled observation of sharp spectral features related to the spin transitions of different excitations of these systems. The analysis of the experimental data allowed determination of the nature of these excitations as well as their parameters, leading thus to a better understanding of the properties of the systems studied. (author)Available from British Library Document Supply Centre-DSC:DXN041299 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Second life of electric vehicle batteries: relation between materials degradation and environmental impact

Nowadays, the electric vehicle is one of the most promising alternatives for sustainable transportation. However, the battery, which is one of the most important components, is the main contributor to environmental impact and faces recycling issues. In order to reduce the carbon footprint and to minimize the overall recycling processes, this paper introduces the concept of re-use of electric vehicle batteries, analyzing some possible second-life applications. Methods First, the boundaries of the life cycle assessment of an electric vehicle are defined, considering the use of the battery in a second-life application. To perform the study, we present eight different scenarios for the second-life application. For each case, the energy, the efficiency, and the lifetime of the battery are calculated. Additionally, and based on the global warming potential, the environmental impact of the electric vehicle and its battery on a second-life application is determined for each scenario. Finally, an environmentally focused discussion on battery electrodes and research trends is presented. Results and discussion For the selected scenarios, the second life of the battery varies from 8 to 20 years depending on the application and the requirements. It has been observed that the batteries connected to the electricity grid for energy arbitrage storage have the highest impact per provided kilowatt hour. On the contrary, the environmental benefit comes from applications working with renewable energy sources and presenting a longer lifetime. We pointed out that a correlation between cycling conditions and degradation mechanisms of the electrode materials is compulsory for proper use of the electric vehicle battery in a second-life application. Conclusions To limit the environmental impact, batteries should be associated with renewable energy sources in stationary applications. However, it is more profitable to re-use Li-ion batteries than to use new lead-acid batteries. Although many batteries applied for electric vehicles use graphite-based anodes, the latter may not be the most suitable for the second-life application. A better understanding of Li-ion battery degradation during the second-life application is required for the different existing chemistries

High-temperature conductivity evaluation of Nb doped SrTiO 3 thin films: Influence of strain and growth mechanism

Doped SrTiO3 thin films, 55 nm thick, were epitaxially grown by Pulsed Laser Deposition with niobium contents ranging from 2 to 5 mol% on SrTiO3 and LaAlO3 substrates. The different templates result in different growth defects, film growth mechanism and therefore a different volume fraction of uniformly strained film under the critical thickness. The investigation of the conductivity reveals a significant difference between the two substrate choices, but only at elevated temperatures with conductivity values up to 30% larger for films on SrTiO3 substrates compared with LaAlO3. Whereas in bulk ceramics the niobium level dictates the total conductivity, here it was found that the substrate choice had a greater influence for thin films, in particular at temperatures over 400 C. This finding provides important information on conductive layers in complex heterostructures where strain and defects could work cooperatively. © 2013 Elsevier B.V. All rights reserved

Plasma cholesterol is excreted in the feces of patients with complete common bile duct obstruction : in vivo evidence for tice pathway in humans

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Dual Substitution Strategy to Enhance Li+ Ionic Conductivity in Li7La3Zr2O12 Solid Electrolyte

Solid state electrolytes could address the current safety concerns of lithium-ion batteries as well as provide higher electrochemical stability and energy density. Among solid electrolyte contenders, garnet-structured Li7La3Zr2O12 appears as a particularly promising material owing to its wide electrochemical stability window; however, its ionic conductivity remains an order of magnitude below that of ubiquitous liquid electrolytes. Here, we present an innovative dual substitution strategy developed to enhance Li-ion mobility in garnet-structured solid electrolytes. A first dopant cation, Ga3+, is introduced on the Li sites to stabilize the fast-conducting cubic phase. Simultaneously, a second cation, Sc3+, is used to partially populate the Zr sites, which consequently increases the concentration of Li ions by charge compensation. This aliovalent dual substitution strategy allows fine-tuning of the number of charge carriers in the cubic Li7La3Zr2O12 according to the resulting stoichiometry, Li7–3x+yGaxLa3Zr2–yScyO12. The coexistence of Ga and Sc cations in the garnet structure is confirmed by a set of simulation and experimental techniques: DFT calculations, XRD, ICP, SEM, STEM, EDS, solid state NMR, and EIS. This thorough characterization highlights a particular cationic distribution in Li6.65Ga0.15La3Zr1.90Sc0.10O12, with preferential Ga3+ occupation of tetrahedral Li24d sites over the distorted octahedral Li96h sites. 7Li NMR reveals a heterogeneous distribution of Li charge carriers with distinct mobilities. This unique Li local structure has a beneficial effect on the transport properties of the garnet, enhancing the ionic conductivity and lowering the activation energy, with values of 1.8 × 10–3 S cm–1 at 300 K and 0.29 eV in the temperature range of 180 to 340 K, respectively

Enhancing the polymer electrolyte – Li metal interface on highvoltage solid-state batteries with Li-based additives inspired by the surface chemistry of Li₇La₃Zr₂O₁₂

High-voltage Li metal solid-state batteries are in the spotlight of high energy and power density devices for the next generation of batteries. However, the lack of robust solid-electrolyte interfaces (SEI) and the propagation of Li dendrites still need to be addressed for practical application with extended cyclability. In the present work, high-voltage Li metal cells with LiNi0.6Mn0.2Co0.2O2 active material were assembled with a polyethylene(oxide) based electrolyte mixed with bis(fluorosulfonyl)imide (LiFSI) salt. The addition of Li7La3Zr2012 garnet to form a composite electrolyte demonstrated the beneficial effect for cell cycling stability. Inspired by the improved interface of ceramic Li7La3Zr2012 garnet and Li metal, as well as by previous knowledge on favorable SEI forming species, various additive candidates were selected to optimize its electrolyte composition. Among them, lithium hydroxide (LiOH) is a key favorable specie that shows a relevant improvement on the cyclability of the cells. X-ray photoelectron spectroscopy showed that the SEI layer is composed mainly by chemical species arising from the reduction of the Li salt, being the lithium fluoride (LiF) the main product. In addition, solid-state nuclear magnetic resonance proved that LiOH induces the cleavage of the labile S-F bond, increasing the concentration of LiF. Herein, we highlight that SEI-forming additives need to be considered for the interfacial engineering design of stable SEI to expand the performance boundary of SSBs.National Research Foundation (NRF)Submitted/Accepted versionW. M. and M. S. are thankful for the financial support from the National Research Foundation of Singapore (NRF) under Investigatorship Award Number NRFI2017-08

In vivo evidence for transintestinal cholesterol efflux in patients with complete common bile duct obstruction

International audienceBackground: Beyond the hepatobiliary pathway, studies have demonstrated that direct TransIntestinal Cholesterol Efflux (TICE) of plasma-derived cholesterol may contribute to reverse cholesterol transport. The clinical evidence of TICE in human remains challenged due to the difficulty to discriminate the hepatobiliary and transintestinal routes in vivo. Objective: To provide the first proof of concept that TICE exists in vivo in humans by demonstrating that plasma labeled cholesterol can be excreted in the feces of patients with complete bile duct obstruction. Methods: Plasma, bile and fecal cholesterol excretion was measured by mass spectrometry 24, 48 and 72h after intravenous injection of D7-cholesterol in two patients presenting cholangiocarcinomas with a total obstruction of their primary bile duct. Results: No trace of bile acids was detected in the feces of the two patients. Despite this, a significant amount of plasma D7-cholesterol was quantified in the feces of the two patients 48h and 72h after the intravenous injection. Conclusion: our data bring a direct proof that TICE is an active pathway in humans. ClinicalTrials.gov Registration number: NCT01958216 Highlights: The transintestinal (TICE) route is crucial for plasma cholesterol excretion in rodent To date, the physiological relevance of TICE in humans remains questioned Patients with obstructed biliary route can excrete plasma cholesterol in their feces TICE is an active pathway in human

Plasma cholesterol is excreted in the feces of patients with complete common bile duct obstruction : in vivo evidence for tice pathway in humans

International audienc