Single-ion conducting polymer electrolyte for Li||LiNi0.6_{0.6}Mn0.2_{0.2}Co0.2_{0.2}O2_{2} batteries—impact of the anodic cutoff voltage and ambient temperature

Polymer-based electrolytes potentially enable enhanced safety and increased energy density of lithium-metal batteries employing high capacity, transition metal oxide-positive electrodes. Herein, we report the investigation of lithium-metal battery cells comprising Li[Ni$_{0.6}$Mn$_{0.2}$Co$_{0.2}$]O$_{2}$ as active material for the positive electrode and a poly(arylene ether sulfone)-based single-ion conductor as the electrolyte incorporating ethylene carbonate (EC) as selectively coordinating molecular transporter. The resulting lithium-metal battery cells provide very stable cycling for more than 300 cycles accompanied by excellent average Coulombic efficiency (99.95%) at an anodic cutoff potential of 4.2 V. To further increase the achievable energy density, the stepwise increase to 4.3 V and 4.4 V is herein investigated, highlighting that the polymer electrolyte offers comparable cycling stability, at least, as common liquid organic electrolytes. Moreover, the impact of temperature and the EC content on the rate capability is evaluated, showing that the cells with a higher EC content offer a capacity retention at 2C rate equal to 61% of the capacity recorded at 0.05 C at 60 degrees C

Nanocrystalline cellulose reinforced poly(ethylene oxide) electrolytes for lithium-metal batteries with excellent cycling stability

Polyethylene oxide (PEO) based polymer electrolytes are still the state of the art for commercial lithium-metal batteries (LMBs) despite their remaining challenges such as the limited ionic conductivity at ambient temperature. Accordingly, the realization of thin electrolyte membranes and, thus, higher conductance is even more important, but this requires a sufficiently high mechanical strength. Herein, the incorporation of nanocrystalline cellulose into PEO-based electrolyte membranes is investigated with a specific focus on the electrochemical properties and the compatibility with lithium-metal and LiFePO$_4$-based electrodes. The excellent cycling stability of symmetric Li||Li cells, including the complete stripping of lithium from one electrode to the other, and Li||LiFePO$_4$ cells renders this approach very promising for eventually yielding thin high-performance electrolyte membranes for LMBs

Simulating competitive egress of noncircular pedestrians

We present a numerical framework to simulate pedestrian dynamics in highly competitive conditions by means of a force-based model implemented with spherocylindrical particles instead of the traditional, symmetric disks. This modification of the individuals' shape allows one to naturally reproduce recent experimental findings of room evacuations through narrow doors in situations where the contact pressure among the pedestrians was rather large. In particular, we obtain a power-law tail distribution of the time lapses between the passage of consecutive individuals. In addition, we show that this improvement leads to new features where the particles' rotation acquires great significance

Pristine and modified porous membranes for zinc slurry–air flow battery

The membrane is a crucial component of Zn slurry–air flow battery since it provides ionic conductivity between the electrodes while avoiding the mixing of the two compartments. Herein, six commercial membranes (Cellophane™ 350PØØ, Zirfon®, Fumatech® PBI, Celgard® 3501, 3401 and 5550) were first characterized in terms of electrolyte uptake, ion conductivity and zincate ion crossover, and tested in Zn slurry–air flow battery. The peak power density of the battery employing the membranes was found to depend on the in-situ cell resistance. Among them, the cell using Celgard® 3501 membrane, with in-situ area resistance of 2 Ω cm$^{2}$ at room temperature displayed the highest peak power density (90 mW cm−2). However, due to the porous nature of most of these membranes, a significant crossover of zincate ions was observed. To address this issue, an ion-selective ionomer containing modified poly(phenylene oxide) (PPO) and N-spirocyclic quaternary ammonium monomer was coated on a Celgard® 3501 membrane and crosslinked via UV irradiation (PPO-3.45 + 3501). Moreover, commercial FAA-3 solutions (FAA, Fumatech) were coated for comparison purpose. The successful impregnation of the membrane with the anion-exchange polymers was confirmed by SEM, FTIR and Hg porosimetry. The PPO-3.45 + 3501 membrane exhibited 18 times lower zincate ions crossover compared to that of the pristine membrane (5.2 × 10$^{-13}$ vs. 9.2 × 10$^{-12}$ m$^{2}$ s$^{-1}$). With low zincate ions crossover and a peak power density of 66 mW cm$^{-2}$, the prepared membrane is a suitable candidate for rechargeable Zn slurry–air flow batteries

L’électrolyte, un élément clé des batteries

National audienceElectrolytes, at the heart of electrochemical generators, ensure the transport of ions from one electrode to another and are an essential element in the design of the "ideal" battery. The electrolyte must adapt to the electrode materials used and the operating conditions, so several electrolyte family has been developed. Once the properties required for the electrolytes have been defined, the recent advances obtained for these different electrolytes will be developed.Les électrolytes, au cœur des générateurs électrochimiques, assurent le transport des ions d’une électrode à l’autre et sont un élément essentiel dans la conception de la batterie « idéale ». L’électrolyte doit s’adapter aux matériaux d’électrode utilisés et aux conditions de fonctionnement, il existe ainsi différentes familles d’électrolytes. Après la définition des propriétés requises pour les électrolytes, les avancées récentes obtenues pour ces différents électrolytes seront développées

L’électrolyte, un élément clé des batteries

National audienceElectrolytes, at the heart of electrochemical generators, ensure the transport of ions from one electrode to another and are an essential element in the design of the "ideal" battery. The electrolyte must adapt to the electrode materials used and the operating conditions, so several electrolyte family has been developed. Once the properties required for the electrolytes have been defined, the recent advances obtained for these different electrolytes will be developed.Les électrolytes, au cœur des générateurs électrochimiques, assurent le transport des ions d’une électrode à l’autre et sont un élément essentiel dans la conception de la batterie « idéale ». L’électrolyte doit s’adapter aux matériaux d’électrode utilisés et aux conditions de fonctionnement, il existe ainsi différentes familles d’électrolytes. Après la définition des propriétés requises pour les électrolytes, les avancées récentes obtenues pour ces différents électrolytes seront développées