Benjamin D Kohn

Mr. Benjamin D Kohn

orcid

Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 February 2021 in International Journal of Biological Macromolecules
Verified
Journal Article
Closed access
JWJanek Weißpflog
Janek Weißpflog
DVDavid Vehlow
David Vehlow
MMMartin Müller
Martin Müller
BKBenjamin D Kohn
Benjamin D Kohn
USUlrich Scheler
Ulrich Scheler
SSSimona Schwarz
Simona Schwarz

24 January 2022 in Angewandte Chemie International Edition
Verified
Journal Article
Open access
PDF file
Gang WangGang Wang
Gang Wang
EDEvgenia Dmitrieva
Evgenia Dmitrieva
BKBenjamin D Kohn
Benjamin D Kohn
USUlrich Scheler
Ulrich Scheler
YLYannan Liu
Yannan Liu
XFXinliang Feng
Xinliang Feng
Rechargeable aluminium (Al) batteries (RABs) have long‐been pursued due to the high sustainability and three‐electron‐transfer properties of Al metal. However, limited redox chemistry is available for rechargeable Al batteries, which restricts the exploration of cathode materials. Herein, we demonstrate an efficient Al–amine battery based on a quaternization reaction, in which nitrogen (radical) cations (R3N.+ or R4N+) are formed to store the anionic Al complex. The reactive aromatic amine molecules further oligomerize during cycling, inhibiting amine dissolution into the electrolyte. Consequently, the constructed Al–amine battery exhibits a high reversible capacity of 135 mAh g−1 along with a superior cycling life (4000 cycles), fast charge capability and a high energy efficiency of 94.2 %. Moreover, the Al–amine battery shows excellent stability against self‐discharge, far beyond conventional Al–graphite batteries. Our findings pave an avenue to advance the chemistry of RABs and thus battery performance.

7 November 2018 in Polymers
Verified
Journal Article
Open access
PDF file
BWBrigitte Wiesner
Brigitte Wiesner
BKBenjamin D Kohn
Benjamin D Kohn
MMMandy Mende
Mandy Mende
USUlrich Scheler
Ulrich Scheler
The local dynamics in polymer melts and the impact of external shear in a Couette geometry have been investigated using rheological nuclear magnetic resonance (NMR). The spin-spin relaxation time, T2, which is sensitive to chain-segment motion, has been measured as a function of shear rate for two samples of poly(dimethylsiloxane). For the low-molecular-weight sample, a mono-exponential decay is observed, which becomes slightly faster with shear, indicating restrictions of the polymer chain motion. For the high-weight sample, a much faster bi-exponential decay is observed, indicative of entanglements. Both components in this decay become longer with shear. This implies that the free polymer segments between entanglements become effectively longer as a result of shear.

13 January 2022 in Angewandte Chemie
Verified
Journal Article
Open access
PDF file
Gang WangGang Wang
Gang Wang
EDEvgenia Dmitrieva
Evgenia Dmitrieva
BKBenjamin D Kohn
Benjamin D Kohn
USUlrich Scheler
Ulrich Scheler
YLYannan Liu
Yannan Liu
XFXinliang Feng
Xinliang Feng
Rechargeable aluminium (Al) batteries (RABs) have long‐been pursued due to the high sustainability and three‐electron‐transfer properties of Al metal. However, limited redox chemistry is available for rechargeable Al batteries, which restricts the exploration of cathode materials. Herein, we demonstrate an efficient Al–amine battery based on a quaternization reaction, in which nitrogen (radical) cations (R3N.+ or R4N+) are formed to store the anionic Al complex. The reactive aromatic amine molecules further oligomerize during cycling, inhibiting amine dissolution into the electrolyte. Consequently, the constructed Al–amine battery exhibits a high reversible capacity of 135 mAh g−1 along with a superior cycling life (4000 cycles), fast charge capability and a high energy efficiency of 94.2 %. Moreover, the Al–amine battery shows excellent stability against self‐discharge, far beyond conventional Al–graphite batteries. Our findings pave an avenue to advance the chemistry of RABs and thus battery performance.

1 July 2022 in Physics of Fluids
Verified
Journal Article
Open access
PDF file
BKBenjamin D Kohn
Benjamin D Kohn
EWErik Walinda
Erik Walinda
KSKenji Sugase
Kenji Sugase
DMDaichi Morimoto
Daichi Morimoto
USUlrich Scheler
Ulrich Scheler
Flow patterns including counter-flow and flow reversal effects have been studied by a combination of nuclear magnetic resonance flow imaging and numerical modeling using the finite volume method in the open-source computational fluid mechanics package OpenFOAM. Two cylindrical geometries have been used: In a concentric double-cylinder system the flow reversal under oscillatory rotation of the inner cylinder has been followed, and the time evolution of the flow reversal has been studied. We find extended periods of counter-rotating flow in the gap where fluid in the inner part of the gap follows the new direction of the rotor, while the outer part takes a longer time until the viscous forces transmit the reverted flow direction outwards. The radial position of the reversal of flow direction has been monitored as a function of the oscillation angle after the turning point. In the second cylindrical geometry, the rotating bob is placed off the center and a counter-rotating vortex is detected in the wider part of the gap. At constant viscosity and eccentricity, the position of the center of the vortex was found to depend on the rotation frequency of the bob. Qualitative and quantitative agreement between experiment and laminar (nonturbulent) flow simulations has been obtained for both steady-state flow using the Semi-Implicit Method for Pressure Linked Equations (SIMPLE) algorithm and time-dependent flow using the Pressure Implicit with Splitting of Operators (PISO) algorithm.

17 April 2023 in Journal of Colloid and Interface Science
Verified
Journal Article
Closed access
BRBerthold Reis
Berthold Reis
KBKonstantin B. L. Borchert
Konstantin B. L. Borchert
CSChristine Steinbach
Christine Steinbach
BKBenjamin D Kohn
Benjamin D Kohn
USUlrich Scheler
Ulrich Scheler
SSSimona Schwarz
Simona Schwarz