Electrochemical Migration Behavior of Ag Electrodes in Negative Temperature Coefficient (NTC) Sensors Under Complex Environmental Conditions
Year: 2026
Type: article
Abstract: To investigate electrochemical migration (ECM) and related failure of Ag electrodes in negative temperature coefficient (NTC) sensors under complex environments, screen-printed coplanar Ag electrodes were tested by means of real-time resistance monitoring and in situ CCD (Charge-Coupled Device) observation. The effects of water films, applied bias, NaCl concentration, and solution pH were examined. No observable migration occurred at 80 °C and 3 V without liquid water. In pure water, Ag dendrites grew from the cathode toward the anode and formed conductive bridges; increasing the bias from 3 to 4 V shortened the time to short circuit. In neutral NaCl media, 0.1 mmol L−1 NaCl allowed Ag-containing species to migrate across the electrode gap and form dendrites, whereas 1 and 5 mmol L−1 NaCl promoted AgCl-related deposits that suppressed sustained Ag dissolution, with the extent of inhibition depending on dissolution flux and surface coverage. In HCl media, surface deposits provided insufficient long-term protection, leading to continued Ag dissolution and short-circuit failure. In Na2CO3 media at pH = 9 and pH = 12, insoluble Ag-containing deposits formed on the anode and no dendritic bridging was observed. Overall, Ag ECM is governed by the competition among anodic dissolution, surface deposition/passivation, and the transport of Ag-containing species across the electrode gap. The results provide a basis for material selection, package design, and reliability assessment of NTC sensors for power batteries.
Source: Materials
DOI: 10.3390/ma19214510
Institution: Tsinghua Shenzhen International Graduate School
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,137
OpenAlex ID: W7223936605