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The formation of effective interphases is crucial to enable high‐performance lithium‐ion batteries. This can be facilitated by the introduction of electrolyte additives, ensuring improved stability and transport properties. The identification of proper additives requires a comprehensive understanding of the fundamental mechanisms of interfacial reactions governing interphase formation. This study presents a detailed investigation of widely known and less conventional interphase‐forming additives in high‐voltage LiNi0.6Mn0.2Co0.2O2, NMC622||artificial graphite cells. The electrochemical characterization shows that cells containing vinylethylene carbonate (VEC) significantly outperform all other investigated electrolyte formulations. Surprisingly, gas chromatography‐mass spectroscopy measurements of the electrolyte composition after cycling indicate the formation of an ineffective solid‐electrolyte interphase (SEI) in the presence of VEC. A thorough analysis of the interfacial composition via operando shell‐isolated nanoparticle‐enhanced Raman spectroscopy (SHINERS) and surface‐enhanced Raman spectroscopy elucidates rather the formation of an effective cathode‐electrolyte interphase (CEI). This phenomenon results from the reductive reaction of VEC on the anode, followed by the product transfer and electro‐polymerization of reaction products on the cathode. Additionally, focused ion beam secondary ion mass spectrometry (FIB‐SIMS) with a time of flight (ToF)‐detector is used to analyze the elemental spatial distribution of Li‐species and Mn in the respective SEIs. [ABSTRACT FROM AUTHOR]

Among the technologies used for spent lithium-ion battery recycling, the common approaches include mechanical treatment, pyrometallurgical processing and hydrometallurgical processing. These technologies do not stand alone in a complete recycling process but are combined. The constant changes in battery materials and battery design make it a challenge for the existing recycling processes, and the need to design efficient and robust recycling processes for current and future battery materials has become a critical issue today. Therefore, this paper simplifies the current treatment technologies into three recycling routes, namely, the hot pyrometallurgical route, warm mechanical route and cold mechanical route. By using the same feedstock, the three routes are compared based on the recovery rate of the six elements (Al, Cu, C, Li, Co and Ni). The three different recycling routes represent specific application scenarios, each with their own advantages and disadvantages. In the hot pyrometallurgical route, the recovery of Co is over 98%, and the recovery of Ni is over 99%. In the warm mechanical route, the recovery of Li can reach 63%, and the recovery of graphite is 75%. In the cold mechanical route, the recovery of Cu can reach 75%, and the recovery of Al is 87%. As the chemical compositions of battery materials and various doping elements continue to change today, these three recycling routes could be combined in some way to improve the overall recycling efficiency of batteries. [ABSTRACT FROM AUTHOR]

Losses of Li inventory in lithium‐ion batteries lead to losses in capacity and can be compensated by electrode prelithiation before cell assembly or before cell formation. The approach of chemical prelithiation, for example, via Li arene complex (LAC)‐based solutions is technically an apparently simple and promising approach. Nevertheless, as shown herein on the example of Si‐based anodes and LAC solutions based on 4,4′‐dimethylbiphenyl (4,4′‐DMBP), several practical challenges need to be considered. Given their reactivity, the LAC solution can not only decompose itself within a range of a few hours, as seen by discoloration and confirmed via mass spectrometry, but can also decompose its solvent and binder of added composite electrodes. Effective prelithiation requires an excess in capacity of the LAC solution (relative to anode capacity) and optimized system characteristic conditions (time, temperature, etc.) as exemplarily shown by comparing Si‐based nanoparticles with nanowires. It is worth noting that the prelithiation degree alone does not determine the boost in cycle life, but relevantly depends on previously applied prelithiation conditions (e.g., temperature), as well. [ABSTRACT FROM AUTHOR]

Herein we report on an analytical approach for targeted identification of hazardous 1,3‐propane sultone (PS) in spent lithium ion battery material. PS decomposition is investigated with chromatographic techniques coupled to high‐resolution accurate mass spectrometry. Speciation of sulfur‐containing decomposition products is performed and aging marker molecules are defined. The observed PS decomposition results in characteristic 1‐propanesulfonate via electrochemical ring‐opening. Based on this, 1‐propanesulfonate is defined as an ionic marker molecule for electrochemical PS decomposition. Further, volatile methyl and ethyl esters of 1‐propanesulfonate are identified. Their formation is observed mainly caused by elevated temperatures after preceding PS ring‐opening during cell formation. Both, ionic and volatile decomposition markers can be applied for targeted identification of hazardous PS‐containing lithium ion battery material, despite possible consumption of the initial additive molecule. [ABSTRACT FROM AUTHOR]

In this study, the hyphenation of gas chromatography to atmospheric pressure chemical ionization-quadrupole-time-of-flight-mass spectrometry (GC-APCI-Q-TOF-MS) is applied for the investigation of degradation products of ionic liquid (IL) based electrolytes. The advantage of APCI compared to electron ionization (EI) for amine-based analytes due to a higher sensitivity of the molecular ion was demonstrated and the results obtained in this work contribute to a better understanding of the IL aging behavior in regard to their application as green electrolyte for lithium metal batteries (LMBs). Pristine N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide (Pyr14TFSI) and Pyr14TFSI-based electrolytes with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as conducting Li salt were investigated. For this purpose, ion source optimization was performed for amine-based analytes using N-butyl-N-methylbutan-1-amine (BMBA) as standard compound. Furthermore, a customized water flow was directed into the ion source to inhibit in-source reactions, such as fragmentation or oxidation processes, and therefore to promote the [M+H]+-ion formation. The respective headspace (HS) above the ionic liquids (ILs) and electrolytes was sampled at first for the detection of highly volatile analytes. Structure proposals were provided by matching mass spectra obtained from GC-APCI-Q-TOF-MS/MS and GC-EI-MS measurements. Aliphatic amine-, pyrrolidine- and pyrrole-based aging products were identified as decomposition species of the Pyr14 +-cation, e.g. N-butylpyrrole and N-butyl-N-methylpent-4-en-1-amine. Furthermore, the presence of lithium metal on a copper substrate in the pristine IL led to significantly stronger aging effects. Galvanic corrosion processes at the redox-couple Li and Cu were suggested as possible causes. This phenomenon questions the practicability of using copper current collectors with lithium anodes for IL-based battery cell systems. Additionally, the LiTFSI concentration in the electrolyte showed an impact on aging caused by corrosion. [ABSTRACT FROM AUTHOR]

The decomposition of state‐of‐the‐art lithium ion battery (LIB) electrolytes leads to a highly complex mixture during battery cell operation. Furthermore, thermal strain by e.g., fast charging can initiate the degradation and generate various compounds. The correlation of electrolyte decomposition products and LIB performance fading over life‐time is mainly unknown. The thermal and electrochemical degradation in electrolytes comprising 1 m LiPF6 dissolved in 13C3‐labeled ethylene carbonate (EC) and unlabeled diethyl carbonate is investigated and the corresponding reaction pathways are postulated. Furthermore, a fragmentation mechanism assumption for oligomeric compounds is depicted. Soluble decomposition products classes are examined and evaluated with liquid chromatography‐high resolution mass spectrometry. This study proposes a formation scheme for oligo phosphates as well as contradictory findings regarding phosphate‐carbonates, disproving monoglycolate methyl/ethyl carbonate as the central reactive species. [ABSTRACT FROM AUTHOR]

Front Cover: Accessing the Primary Solid-Electrolyte Interphase on Lithium Metal: A Method for Low-Concentration Compound Analysis (ChemSusChem 9/2023) Keywords: batteries; lithium; mass spectrometry; NMR spectroscopy; solid-electrolyte interphases EN batteries lithium mass spectrometry NMR spectroscopy solid-electrolyte interphases 1 1 1 05/09/23 20230505 NES 230505 Mining for information on the solid-electrolyte interphase (SEI) on lithium metal electrodes: B The Front Cover b shows a representation of the method that was developed in the group of Prof. Dr. Martin Winter within the division for Analytics and Environment. Batteries, lithium, mass spectrometry, NMR spectroscopy, solid-electrolyte interphases. [Extracted from the article]

Herein we report on an analytical study of dry-shredded lithium-ion battery (LIB) materials with unknown composition. Samples from an industrial recycling process were analyzed concerning the elemental composition and (organic) compound speciation. Deep understanding of the base material for LIB recycling was obtained by identification and analysis of transition metal stoichiometry, current collector metals, base electrolyte and electrolyte additive residues, aging marker molecules and polymer binder fingerprints. For reversed engineering purposes, the main electrode and electrolyte chemistries were traced back to pristine materials. Furthermore, possible lifetime application and accompanied aging was evaluated based on target analysis on characteristic molecules described in literature. With this, the reported analytics provided precious information for value estimation of the undefined spent batteries and enabled tailored recycling process deliberations. The comprehensive feedstock characterization shown in this work paves the way for targeted process control in LIB recycling processes., (© 2022 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)