Battery characterization via eddy-current imaging with nitrogen-vacancy centers in diamond

TL;DR

This paper introduces a microwave-free AC magnetometry technique using NV centers in diamond for noninvasive imaging of solid-state batteries, enabling defect detection with high spatial resolution and magnetic sensitivity.

Contribution

It presents a novel, microwave-free method for battery imaging based on NV centers, achieving high spatial resolution and defect identification in solid-state batteries.

Findings

Spatial resolution of 360 micrometers achieved.

Detected magnetic fields up to 0.04 mT from batteries.

Successfully identified defects and structural anomalies.

Abstract

Sensitive and accurate diagnostic technologies with magnetic sensors are of great importance for identifying and localizing defects of rechargeable solid batteries in a noninvasive detection. We demonstrate a microwave-free AC magnetometry method with negatively charged NV centers in diamond based on a cross-relaxation feature between NV centers and individual substitutional nitrogen (P1) centers occurring at 51.2 mT. We apply the technique to non-destructive solid-state battery imaging. By detecting the eddy-current-induced magnetic field of the battery, we distinguish a defect on the external electrode and identify structural anomalies within the battery body. The achieved spatial resolution is $360\,\mu\rm m$. The maximum magnetic field and phase shift generated by the battery at the modulation frequency of 5 kHz are estimated as 0.04 mT and 0.03 rad respectively.