A5054175182- Advancements in Battery Materials
- Advanced Battery Materials and Technologies
- Advanced Battery Technologies Research
- Advanced battery technologies research
- Catalytic Processes in Materials Science
- Electron and X-Ray Spectroscopy Techniques
- Semiconductor materials and devices
- Electron Spin Resonance Studies
- Analytical Chemistry and Sensors
- Conducting polymers and applications
- Gas Sensing Nanomaterials and Sensors
- Extraction and Separation Processes
- Ionic liquids properties and applications
- Non-Destructive Testing Techniques
- Recycling and Waste Management Techniques
Technical University of Munich
2012-2023
Curtin University
2018
Ludwig-Maximilians-Universität München
2014
Transition metal dissolution from the cathode active material and its deposition on anode causes significant cell aging, studied most intensively for manganese. Owing to their higher specific energy, current focus is shifting towards nickel-rich layered LiNixMnyCozO2 (NMC, x + y z = 1) with > 0.5, so that effect of Ni degradation needs be understood. This study investigates transition metals a NMC622 subsequent graphite using operando X-ray absorption spectroscopy. We show in NMC622-graphite...
<italic>Operando</italic> X-ray absorption spectroscopy studies of transition metal dissolution in Li-ion batteries.
Aprotic lithium-oxygen (Li-O2 ) batteries have attracted considerable attention in recent years owing to their outstanding theoretical energy density. A major challenge is poor reversibility caused by degradation reactions, which mainly occur during battery charge and are still poorly understood. Herein, we show that singlet oxygen ((1) Δg formed upon Li2 O2 oxidation at potentials above 3.5 V. Singlet was detected through a reaction with spin trap form stable radical observed time-...
Time-resolved formation of micro-structured mossy/dendritic lithium is investigated during battery cycling by<italic>operando</italic>EPR spectroscopy, using a novel electrochemical cell design.
High degrees of delithiation layered transition metal oxide cathode active materials (NCMs and HE-NCM) for lithium-ion batteries (LIBs) was shown to lead the release singlet oxygen, which is accompanied by enhanced electrolyte decomposition. Here, we study reactivity chemically produced oxygen with commonly used cyclic linear carbonate solvents LIB electrolytes. On-line gassing analysis decomposition ethylene (EC) dimethyl (DMC) reveals different stability toward chemical attack in situ...
Abstract Aprotic lithium–oxygen (Li–O 2 ) batteries have attracted considerable attention in recent years owing to their outstanding theoretical energy density. A major challenge is poor reversibility caused by degradation reactions, which mainly occur during battery charge and are still poorly understood. Herein, we show that singlet oxygen ( 1 Δ g formed upon Li O oxidation at potentials above 3.5 V. Singlet was detected through a reaction with spin trap form stable radical observed time‐...
The use of 1-methyl-1-butylpyrrolidinium bis(trifluoromethylsulfonyl)imide (Pyr14TFSI) electrolyte in different Li-O2 cell setups is here investigated. In a one-compartment cell, the pyrrolidinium ion reduced on metallic lithium, producing substantial amounts alkenes and amines. To avoid this, simple two-compartment used, with propylene carbonate as anode Li+-ion solid separator. Another explored option substitution lithium lithiated LTO (LLTO). Unfortunately, absence an SEI leads to...
A new operando spectro-electrochemical setup was developed to study oxygen depletion from the surface of layered transition metal oxide particles at high degrees delithiation. An NCM111 working electrode paired with a chemically delithiated LiFePO4 counter in fuel cell-inspired membrane assembly (MEA). propylene carbonate-soaked Li-ion conducting ionomer served as an electrolyte, providing both good electrochemical performance and direct probing during cycling by ambient pressure X-ray...
Aprotic lithium–oxygen (Li-O 2 ) batteries have attracted considerable attention in recent years owing to their outstanding theoretical energy density. [1] Parasitic side reactions are the central problem for development of a reversible Li-O cell chemistry. They mainly occur upon charge, causing degradation both carbon electrode and electrolyte battery cycling, leading death within few cycles. The exact electrochemical or chemical nature during charge remains largely unclear, but some form...
Li-O 2 cells are very promising energy conversion devices because of the theoretical specific capacity that they could provide (1). Unfortunately also challenging regarding instability their components, like electrolyte solvent (2-4) and carbon electrode (5, 6) mostly due to reactivity superoxide ion radical during discharge or other reactive oxygen species in charge. Also binder used O -electrode reactivity, which have a strong effect on reactions (7, 8), even though its cell behavior has...
The formation of micro structured lithium (e.g. mossy/dendritic lithium) during battery charge is known to adversely affect life time due the consumption active and electrolyte also poses a safety risk internal cell shortening. For metal anodes, problem dendrite caused by inhomogeneous plating has been for decades but in spite intensive research no viable solutions have found yet, thus rendering anodes impractical commercial cells. [1] Graphite, which widely used instead, can reversibly...
Graphite is the standard anode material in Li-ion cells due to its high capacity of 372 mAh g -1 , good cycling stability and low price. Lithium ions can reversibly intercalate into graphite host structure at potentials 80 – 120 mV vs. Li/Li + . While intercalation potential favorable terms energy density, it cause lithium plating if are charged rates or temperatures. metal adversely affects cell life loss active electrolyte also poses a serious safety hazard because internal short...
Abstract not Available.
Abstract In this work, we present a detailed investigation of the aging behavior in commercially produced 18650-type cells with graphite/LFP cell chemistry. Two different kinds are investigated, which only differ graphite type used as anode active material, namely mesocarbon microbeads (MCMB) or needle coke (NC). These materials have similar BET surface area (2.4 m 2 g -1 for MCMB, 1.9 NC) but particle shape and morphology (inset Figure 1) ratio exposed basal edge planes. Both showed good...
Currently employed consumer batteries for high energy density applications rely on layered transition metal oxides as cathode active materials due to their theoretical capacity and excellent retention over prolonged cycling. Today’s research focus lies Ni- Li-rich (Li w Ni x Co y Mn z O 2 like NCM811 with w=1, x=0.8, y=z=0.1 or NCM (HE-NCM) w+x+y+z=2 w>1), motivated by a drive towards lower battery cost in $/kWh (1). However, today’s systems can only utilize roughly 70% of the maximum...