TY  - CONF
A1  - Scharpmann, Philippa
T1  - Tracing overdischarge-induced degradation in lithium-ion cells using cyclic voltammetry and differential voltage analysis
N2  - Differential voltage analysis (DVA) and cyclic voltammetry (CV) are powerful
electroanalytical techniques. While CV can be used to study the kinetics of electron transfer reactions [1], DVA can visualise phase transitions by correlating the opencircuit voltage and exchanged charge [2]. Recently, DVA receives an increasing attention in the battery community for characterising full-cell setups. In contrast, CV is less prominent for batteries, yet the prevalently used technique for ex-situ characterisations of novel electrode materials in half-cell configuration. 

In this study, we have investigated the overdischarge process of LiFePO4 pouch cells – which is usually presumed to result in a decomposition of the solid electrolyte interphase (SEI) and a corrosion of the copper current collector – in a complementary electrochemical analysis which uses both, CV and DVA in full-cell mode. For this purpose, CV consisting of three low sweep-rate scans and DVA of three low current rate cycles was performed. Degradation was traced by successive CV/DVA sequences during, pre- and post-overdischarge which allowed to pinpoint the features, the limitations, and similarities of both techniques. 

In this manner, we demonstrate that CV can successfully identify the dynamics of degradation processes, indicating that an irreversible side reaction starts at cell voltages below 0.55 V. For this reason, this study underlines that CV can be effectively used for spotting dynamic degradation mechanisms which are hardy seen in DVA. This may pave the way for further analysis which can be used for fingerprinting characteristic degradation.
T2  - 124. Bunsentagung 2025
CY  - Leipzig, Germany
DA  - 17.03.2025
KW  - Differential Voltage Analysis
KW  - Cyclic Voltammetry
KW  - Batteries
PY  - 2025
AN  - OPUS4-65055
LA  - eng
AD  - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER  -