±«Óătv

 

Jeff Dahn Research Group

dV/dQ Analysis

The voltage of a Li-ion cell is the difference between the positive electrode and the negative electrode potentials as measured versus lithium metal, as shown in the Figure.  During charge discharge cycling the positive and negative electrode curves slip relative to one another

Differential voltage (dV/dQ) and differential capacity (dQ/dV) analysis can be used to measure the alignment of electrodes within a full Li-ion cell without the use of the a 3-electrode cell.  This allows cell degradation mechanisms to be understood.

References

  1. A.J. Smith, J.C. Burns, and J.R. Dahn “High-Precision Differential Capacity Analysis of LiMn2O4/graphite Cells” Electrochem. and Solid-State Lett., 14, A39-A41 (2011).
  2. A.J. Smith and J.R. Dahn “Delta Differential Capacity Analysis” J. Electrochem. Soc., 159, A290-A293 (2012).
  3. A.J. Smith, H.M. Dahn, J.C. Burns, and J.R. Dahn “Long-Term Low-Rate Cycling of LiCoO2/Graphite Li-Ion Cells at 55ºC” J. Electrochem. Soc., 159, A705-A710 (2012).
  4. Hannah. M. Dahn, A.J. Smith, J.C. Burns, D.A. Stevens, and J.R. Dahn “User-Friendly Differential Voltage Analysis Freeware for the Analysis of Degredation Mechanisms in Li-Ion Batteries” J. Electrochem. Soc., 159, A1405-A1409 (2012).