Search

The electrification of the transport sector has created an increasing demand for lithium‐ion batteries that can provide high power intermittently while maintaining a high energy density. Given the difficulty in designing a single redox material with both high power and energy density, electrodes based on composites of several electroactive materials optimized for power or capacity are being studied extensively. Among others, fast‐charging LiFePO4 and high energy Li(NixMnyCoz)O2 are commonly employed in industrial cell manufacturing. This study focuses on comparing different approaches to combining these two active materials into a single electrode. These arrangements were compared using standard electrochemical (dis)charge procedures and using synchrotron X‐ray fluorescence to identify variations in solution concentration gradient formation. The electrochemical performance of the layered electrodes with the high‐power material on top is found to be enhanced relative to its blended electrode counterpart when (dis)charged at the same specific currents. These findings highlight dual‐layer lithium‐ion batteries as an inexpensive way of increasing energy and power density of lithium‐ion batteries as well as a model system to study and exploit the synergistic effects of blended electrodes. [ABSTRACT FROM AUTHOR]

Li-ion batteries that incorporate manganese present several advantages, including low cost and low toxicity. However, these batteries often suffer from dissolution of manganese into the electrolyte solution, severely impeding battery performance. This work describes the quantitative detection of Mn2+ ions in battery relevant environment i.e. non-aqueous electrolyte within an inert atmosphere. To this end, an electrochemical probe was fabricated using electrochemical deposition of a Hg cap onto a 25 μm Pt disk microelectrode. The Pt/Hg microelectrode was fully characterized by optical microscopy, cyclic voltammetry, scanning electrochemical microscopy. Using square wave anodic stripping voltammetry to overcome reproducibility issues with classical linear sweep anodic stripping voltammetry, Mn2+ was quantified in non-aqueous solution with a limit of detection of 14 μM. Finally, using this detection scheme, the trapping ability of aza-15-crown-5 ether and dilithium iminodiacetate was investigated. [ABSTRACT FROM AUTHOR]

Keywords: electrode architecture; power density; fast charge; blended electrode; X-ray fluorescence EN electrode architecture power density fast charge blended electrode X-ray fluorescence 1 1 1 11/07/23 20231102 NES 231102 B The Front Cover b shows Li-metal cells which contain two active materials (red and blue). Front Cover: Exploring the Synergistic Effects of Dual-Layer Electrodes for High Power Li-Ion Batteries (ChemElectroChem 21/2023) Electrode architecture, power density, fast charge, blended electrode, X-ray fluorescence. [Extracted from the article]

The ionic liquid 1‐ethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide was used in the scanning micropipette contact method to extend the electrochemical window of the electrolyte solution and enable the study of lithium‐ion battery materials with higher oxidation potential. Localized electrochemical measurements were performed on lithium iron phosphate particles that were drop‐cast onto a glassy carbon substrate. Investigation of the active materials occurred on a small scale (ca. 10 μm diameter), defined by the area of meniscus contact between the electrolyte solution in the micropipette and the substrate. Our studies showed that the SMCM probe is stable and can be used to analyze high energy lithium‐ion battery materials in the range of 2.5 to 5.1 V vs. Li/Li+. Extended potential, higher efficiency: Scanning micropipette contact method (SMCM) is extended to ionic liquid studies. The potential window for 1‐ethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide (EMI TFSI) ionic liquid is suitable to examine high‐energy lithium‐ion battery materials. The electrochemical properties of lithium iron phosphate (LFP) particles drop‐cast onto a glassy carbon substrate are probed under inert atmosphere. SMCM‐coulombic efficiency of LFP particles in EMI TFSI is estimated to be higher than 90 %. [ABSTRACT FROM AUTHOR]

State-of-the-art scanning probe microscopy (SPM) methods as applied to energy conversion and storage devices, specifically lithium-ion batteries, are reviewed with an emphasis on the electroactive elements. The unique ability of SPM-based methods to provide localized information has proven highly valuable for the in-depth understanding of the fundamental mechanisms, processes, and degradation of lithium-ion batteries (LIBs). As such, SPM analysis is poised to play a strong role in the competition for new higher performing LIBs, especially given the unprecedented choice and availability of SPM techniques tailored to provide physical and chemical information at the nanoscale. [ABSTRACT FROM AUTHOR]

The Back Cover picture represents a paper in which scanning probe microscopy methods applied to energy conversion and storage devices (specifically lithium‐ion batteries) are reviewed, with an emphasis on the electroactive elements. More information can be found in the Review by S. B. Schougaard, J. Mauzeroll, and co‐workers on page 6 in Issue 1, 2017 (DOI: 10.1002/celc.201600571). [ABSTRACT FROM AUTHOR]

[Display omitted] • Pulse field gradient nuclear magnetic resonance (PFG-NMR) measurement of electrolyte transport. • Proof of concept measurement on the impact dissolved gasses on D Li + . • CO 2(g) has no measurable effect on the solution phase Li+ diffusion coefficient. Electrolyte decomposition in Li-ion batteries (LIB) and its entailing gas evolution significantly impacts cell performance. CO 2 is one of the most abundantly evolved gases from common LIB electrolytes and could potentially affect Li+ solution transport during LIB operation. To this end, a comparative analysis of the Li+ diffusion coefficient (D Li + ) which governs mass transport is required. Herein a methodology is established to saturate common battery electrolytes with a soluble gas without introducing other contaminants, so as to determine D Li + in saturated and unsaturated samples. As a proof of concept, the values of D Li + are determined in 1 M LiPF 6 and 1 M LiClO 4 in ethylene carbonate (EC):dimethyl carbonate (DMC) with and without dissolved CO 2 , confirmed by gas chromatography–mass spectrometry (GC–MS). The results obtained by pulse field gradient nuclear magnetic resonance (PFG-NMR) diffusion measurements agree for both electrolytes; saturating the electrolyte with CO 2 has no measurable effect on D Li + and therefore does not hinder Li+ mass transport. [ABSTRACT FROM AUTHOR]