In-Situ EIS Extraction: Donghua Instrument

This Workflow processes in-situ EIS records containing multiple Freq(Hz),Zre(Ω),Zim(Ω) blocks (such as 原位EIS数据参考.txt), automatically splitting them into multiple standardized CSV segments. A new segment begins each time a new header is encountered, suitable for electrochemical degradation/trend analysis.

Required Data Format

Partial content:

Segment3(控制电位EIS)
Freq(Hz),Zre(Ω),Zim(Ω)
1E5,2.58944E0,-1.55539E0
7.94328E4,2.71237E0,-1.8413E0
...
Segment6(控制电位EIS)
Freq(Hz),Zre(Ω),Zim(Ω)
1E5,2.59732E0,-1.50046E0
7.94328E4,2.72004E0,-1.76758E0
...

Ensure each EIS segment in the input text contains the following three column headers:

• Freq(Hz)
• Zre(Ω)
• Zim(Ω)

Separated by commas, with subsequent rows being numeric:

Freq(Hz),Zre(Ω),Zim(Ω)
1E5,2.58944E0,-1.55539E0
7.94328E4,2.71237E0,-1.8413E0
...

• Segment* labels are optional; the system does not depend on them.
• A new header is detected whenever Freq(Hz),Zre(Ω),Zim(Ω) is encountered.

Steps

1. Select a single .txt raw input file (single-file interaction).
2. Read the text and split into multiple data blocks by detected headers.
3. Convert each block to unified columns: freq_hz,z_real_ohm,z_imag_ohm,z_mod_ohm,phase_deg.
4. Output directory: <input_filename>_eis_csv, with internal filenames: <input_filename>_eis_001.csv, ....

Output Field Description

• freq_hz: Frequency (Hz, float)
• z_real_ohm: Real part (Ω)
• z_imag_ohm: Imaginary part (Ω)
• z_mod_ohm: Modulus $|Z| = \sqrt{z_{real}^2+z_{imag}^2}$
• phase_deg: Phase angle (°)

Notes

• Rows with frequency <= 0 and invalid numeric rows are filtered out.
• If a segment has no usable data, it will report an error and be skipped.
• The output columns are fully compatible with EIS Extraction: CHI Instrument Data Preprocessing, and can be directly used for subsequent EIS Plotting: Nyquist and Bode Visualization and EIS/DRT Analysis: Mapping Frequency-Domain Impedance to Relaxation Time Distribution analysis.