In Situ Stripline Electrochemical NMR for Batteries

Abstract

Some long‐outstanding technical challenges exist that continue to be of hindrance to fully harnessing the unique investigative advantages of nuclear magnetic resonance (NMR) spectroscopy in the in situ investigation of rechargeable battery chemistry. For instance, the conducting materials and circuitry necessary for an operational battery always deteriorate the coil‐based NMR sensitivity when placed inside the coil, and the shape mismatch between them leads to low sample filling factors and even higher detection limits. We report, herein, a novel and successful adaptation of stripline NMR detection that integrates seamlessly NMR detection with the construction of an electrochemical device in general, or a battery in particular, which leads to an in situ electrochemical NMR technique with much higher detection sensitivity, higher sample filling factor, and which is particularly suitable for mass‐limited samples.

Operando NMR of NMC811/Graphite Lithium-Ion Batteries: Structure, Dynamics, and Lithium Metal Deposition

“…Nuclear magnetic resonance (NMR) spectroscopy is wellsuited for operando measurements on electrochemical cells as it is a non-invasive, non-destructive technique which is sensitive to both structure and dynamics. NMR experiments on LIBs benefit from a comparably high sensitivity since 7 Li (spin-3/2) possesses a high natural abundance (92.4 %), high gyromagnetic ratio (γ( 7 Li)/γ( 1 H) = 0.39) and usually experiences only small quadrupolar couplings. Considerable technical advances have been made in in situ and operando NMR in the past years through the design of dedicated electrochemical cells and NMR probes, [5][6][7][8] some of which now facilitate the advanced studies presented in this paper.…”

“…NMR experiments on LIBs benefit from a comparably high sensitivity since 7 Li (spin-3/2) possesses a high natural abundance (92.4 %), high gyromagnetic ratio (γ( 7 Li)/γ( 1 H) = 0.39) and usually experiences only small quadrupolar couplings. Considerable technical advances have been made in in situ and operando NMR in the past years through the design of dedicated electrochemical cells and NMR probes, [5][6][7][8] some of which now facilitate the advanced studies presented in this paper. Note that we refer to operando measurements as being performed during electrochemical cycling, while in situ measurements are also performed on intact cells, but not necessarily at the same time as charge and discharge.…”

NMR spectroscopy of coin cell batteries with metal casings

“…This tap thus comprises the feed point for a single coaxial cable connection drawn to the bottom of the probe in service of both channels. Sensitivity-optimized detection of nuclei at lower Larmor frequencies such as 13 C or 15 N can be achieved by modifying the position of the tap point. Broadband tuning can also be envisioned for the low-frequency channel by incorporating an additional variable tuning element.…”

An NMR-compatible microfluidic platform enabling in situ electrochemistry

“…The challenge of introducing conductive structures for in situ electrochemical analyses with high-field NMR is reflected by there being only a few reports available. [38][39][40][41][42][43] Microfabrication introduces new opportunities. On one hand, ultra-thin metallic layers, which are NMR transparent, can be achieved by rather standard MEMS techniques.…”