Matthias Kuenzel

Matthias Kuenzel
Karlsruhe Institute of Technology | KIT · Helmholtz Institute Ulm

PhD

About

44
Publications
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622
Citations

Publications

Publications (44)
Article
The use of cobalt-free LiNi0.5Mn1.5O4 (LNMO) would provide a great leap forward towards the realization of sustainable lithium-ion batteries. However, the high operating voltage remains to be a great challenge for the cathode/electrolyte stability. Herein, we report a rational material design to address these challenges by carefully tuning the synt...
Article
Lithium-ion batteries are nowadays playing a pivotal role in our everyday life thanks to their excellent rechargeability, suitable power density, and outstanding energy density. A key component that has paved the way for this success story in the past almost 30 years is graphite, which is serving as lithium-ion host structure for the negative elect...
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Full-text available
Lithium‐rich layered oxides (LRLOs) exhibit specific capacities above 250 mAh g−1, i.e., higher than any of the commercially employed lithium‐ion‐positive electrode materials. Such high capacities result in high specific energies, meeting the tough requirements for electric vehicle applications. However, LRLOs generally suffer from severe capacity...
Article
Rechargeable aqueous batteries are promising devices for large‐scale energy storage applications because of their low‐cost, inherent safety, and environmental friendliness. Among them, aqueous ammonium‐ion (NH4+) batteries (AAIB) are currently emerging owing to the fast diffusion kinetics of NH4+. Nevertheless, it is still a challenge to obtain sta...
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Lithium metal batteries (LMBs) with nickel‐rich cathodes are promising candidates for next‐generation, high‐energy batteries. However, the highly reactive electrodes usually exhibit poor interfacial compatibility with conventional electrolytes, leading to limited cyclability. Herein, a locally concentrated ionic liquid electrolyte (LCILE) consistin...
Article
The reversible and irreversible cationic and anionic charge compensation mechanisms occurring along the first charge and discharge cycle of Li- and Mn-rich Li[Li0.2Ni0.16Mn0.56Co0.08]O2 cathode material at (dis)charge rates of 0.1C and 5C have been identified and quantified by X-ray absorption and emission spectroscopy. The analysis provided the ox...
Article
Ni-rich layered oxides such as Li[Ni0.8Mn0.1Co0.1]O2 (NMC811) are highly sensitive towards moisture. Any contact with humidity leads to the formation of surface contaminants, which reflect into an increased overpotential and cause accelerated capacity loss during cycling. This is particularly relevant when considering large-scale processing. Herein...
Article
Seawater batteries (SWBs) have been mostly researched for large scale energy storage and (sub-) marine applications. In a SWB, the aqueous catholyte (seawater) and a non-aqueous anolyte (aprotic solvent solution)...
Article
The synthesis of a new ionic liquid (IL), consisting of the symmetric tetra-butyl-phosphonium (P4444⁺) cation and the (nonafluorobutanesulfonyl-trifluoromethanesulfonyl) imide (IM14–) anion, via a facile and environmentally-friendly aqueous route is reported. The novel P4444IM14 IL demonstrates excellent thermal and electrochemical stability (beyon...
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High-energy-density lithium-metal batteries face the challenge of developing functional electrolytes enabling both the stabilization of the lithium-metal negative electrode and high-voltage positive electrodes (> 4 V versus Li⁺/Li). Herein, a low-volatility and non-flammable ionic liquid electrolyte (ILE) incorporating two anions, bis(fluorosulfony...
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NASICON-type Li1+xAlxTi2−x(PO4)3 (LATP) solid electrolytes have developed as a promising candidate for solid-state lithium batteries. However, the brittle and stiff LATP suffers from poor physical contact with electrodes and chemical/electrochemical instability at electrode|electrolyte interfaces. Herein, a thin and flexible hybrid electrolyte comp...
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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...
Article
Ionic liquid electrolytes based on imidazolium and tetra-alkyl-ammonium cations, coupled with bis(perfluroalkylsulfonyl)imide anions, are specifically tailored for lithium battery systems operating up to almost 5 V. Their ion transport properties and the electrochemical stability are herein reported and compared. Specifically, the effect of tempera...
Article
Safe and flexible batteries are expected to be the enabler for advancing the technology of wearable electronics to an unforeseen level in near future. However, to date the energy density of such devices is rather limited due to the rather large proportion of dead weight and volume to provide good flexibility. To overcome this hurdle, a disruptive c...
Article
Herein we address the key challenge towards the practical use of high-voltage lithium-ion cathode materials, i.e., the insufficient stability of the electrolyte towards oxidation. The transition metals in such materials, especially nickel, catalyze the decomposition reaction of the electrolyte, ultimately leading to poor cycling stability and rapid...
Article
High-capacity lithium-ion anodes such as alloying-, conversion-, and conversion/alloying-type materials are subjected to extensive volume variation upon de-/lithiation. However, a careful examination of these processes at the particle and electrode level as well as the impact of the kind of lithium-ion uptake mechanism is still missing. Herein, we...
Article
In article number 2001830, Guk‐Tae Kim, Stefano Passerini and co‐workers highlight the benefits of employing ionic‐liquid electrolytes (ILE) in combination with cobalt‐free, lithium‐rich layered oxide positive electrodes. The ILE dramatically reduces the capacity and voltage fading of Li1.2Ni0.2Mn0.6O2 by suppressing the structural decay of the Li1...
Article
In article number 2000783, Gabriele Giuli, Dominic Bresser and co‐workers report the use of Fe‐doped CeO2 as a new active material for lithium‐ion batteries, which combines an insertion‐type mechanism with the reduction of the Fe dopant at the atomic level. Such a fundamentally new mechanism allows for a tripling of the achievable capacity, accompa...
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Full-text available
The development of alternative anode materials with higher volumetric and gravimetric capacity allowing for fast delithiation and, even more important, lithiation is crucial for next‐generation lithium‐ion batteries. Herein, the development of a completely new active material is reported, which follows an insertion‐type lithiation mechanism, metal‐...
Article
Full-text available
Conversion/alloying materials (CAMs) represent a potential alternative for graphite as Li‐ion anodes especially for high power performance. The so far most investigated CAM is carbon‐coated Zn0.9Fe0.1O which provides very high specific capacity of more than 900 mAh g‐1 and good rate capability. Especially for the latter performance, the optimal par...
Article
In article number 2000279, Maximilian Fichtner, Stefano Passerini, and co‐workers demonstrate improved interfacial properties of a lithium lanthanium zirconate (LLZO) solid‐electrolyte (SE)‐based solid‐state battery by employing ionic liquid interlayers at the electrode/electrolyte junctions. This strategy lowers the interfacial resistances and sup...
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Full-text available
The use of water‐soluble, abundant biopolymers as binders for lithium‐ion positive electrodes is being explored because it represents a great step forward towards environmentally benign battery processing. However, so far most studies, employing, for instance, carboxymethyl cellulose (CMC) as binder, have focused on rather low electrode areal loadi...
Article
Full-text available
Li-garnets are promising inorganic ceramic solid electrolytes for lithium metal batteries, showing good electrochemical stability with Li anode. However, their brittle and stiff nature restricts their intimate contact with both the electrodes, hence presenting high interfacial resistance to the ionic mobility. To address this issue, a strategy empl...
Article
A simple model system towards an impedance-probing strain sensor based on conducting tough hydrogels is demonstrated. A poly(acrylamide) hydrogel, cross-linked with N,N’-methylene-bis(acrylamide) was contacted with carbon fibres for electrical impedance analysis. The conductivity of the salt-containing hydrogel was determined to be 114 ± 10 mS/cm....
Article
Invited for this month's cover picture is the group of Prof. Dr. Stefano Passerini. The front cover illustrates the use of citric acid (co‐)crosslinked bio‐derived polymers, with chitosan and guar gum, as water‐soluble binders for sustainable lithium‐ion battery cathodes. Read the full text of the Article at 10.1002/batt.201900140. “The aqueous ele...
Article
The Cover Feature illustrates the use of citric acid (co‐)crosslinked bio‐derived polymers, with chitosan and guar gum, as water‐soluble binders for sustainable lithium‐ion battery cathodes.More information can be found in the Article by M. Kuenzel et al.
Article
Implementing aqueous electrode processing for lithium-ion cathodes is one of the key steps towards the achievement of environmentally benign battery production and of utmost importance in light of their rapidly growing relevance for electric vehicles. Towards this necessity, we present herein a sophisticated approach, specifically addressing the re...
Article
In article number 1902445, Guk‐Tae Kim, Stefano Passerini, and co‐workers reveal the impact of iron doping on the performance fading mechanism of Co‐free Li‐rich (LRNM) layered oxide positive electrode materials. The introduction of iron reduces nickel migration into the transition metal layer and helps to suppress the accompanying structural trans...
Article
Full-text available
The eco‐friendly and low‐cost Co‐free Li1.2Mn0.585Ni0.185Fe0.03O2 is investigated as a positive material for Li‐ion batteries. The electrochemical performance of the 3 at% Fe‐doped material exhibits an optimal performance with a capacity and voltage retention of 70 and 95%, respectively, after 200 cycles at 1C. The effect of iron doping on the elec...
Article
The implementation of aqueous electrode processing for lithium‐ion positive electrodes is key towards the realization of environmentally benign and cheap battery production. One of the water‐soluble binders that has attracted most attention is chitosan, the second‐most abundant natural biopolymer. Herein, the use of chitosan for high‐voltage, cobal...
Article
The electrochemical properties of P2- Na2/3Mn0.8Fe0.1Ti0.1O2 layered oxide, which is a promising cathode material for rechargeable Na-ion batteries (NIBs), are evaluated with with an optimized in-house ionic liquid (IL)-based electrolyte and compared with its performance when using carbonate-based electrolyte. The IL-based system reveals better ele...
Article
Full-text available
LiNi 0.5 Mn 1.5 O 4 (LNMO), which has an operating voltage of 4.8 vs Li/Li ⁺ and a theoretical capacity of 147 mAh g ⁻¹ , is an interesting cathode material for advanced lithium ion batteries. However, electrolyte decomposition at the electrode can gradually decrease the capacity of the battery. In this study, the surface of the LNMO cathode has be...
Article
The Cover Feature shows a complementary strategy to enable the aqueous processing of high-voltage LiNi0.5Mn1.5O4 cathodes for greener and more sustainable lithium-ion batteries. The synergistic combination of phosphoric acid and crosslinked sodium carboxymethyl cellulose (by means of citric acid) provides electrodes with improved capacity, coulombi...
Article
Increasing the environmental benignity of lithium-ion batteries is one of the greatest challenges for their large-scale deployment. Toward this end, we present herein a strategy to enable the aqueous processing of high-voltage LiNi0.5Mn1.5O4 (LNMO) cathodes, which are considered highly, if not the most, promising for the realization of cobalt-free...

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