We know that OCV of graphite anode vs Li/Li+ is approximately 0.4 V, So how it is possible to get the potential level of 4 V vs Li/Li+ in the graphite anode in overdischarge tests ?
Please take a look at the attached figure in which an overdischarge test has been applied on LiCoO2/graphite battery cell. What is interesting for me, is the potential of the cathode which is not changing during overdiscarge.
1st Question) As we know during the discharge process, electrons enter the cathode through the external circuit which the cathode potential need to be decreased not being constant. So, why in this curve, cathode potential is not changing ?
2nd Question) How the potential of 4 V vs Li/Li+ is accessible on anode material (i.e. graphite anode) by taking this into consideration that OCV of graphite vs Li/Li+ is about 0.4 V and if the operating potential get over that, graphite experinces anodic reaction and will be corroded and destroyed at such high potentials of 4 V.
Please propose your technical notes in terms of electrochemical aspects
Dear Askar Soltani ,
what is the origin (ref.?) of the attached (fabricated) figure ?
Also, what is actually measured (and how/conditions), as well as what is estimated (calculated) in the attached figure ?
Dear Ioannis Samaras
Thanks for your interest in my question. Please find the attached paper as the referenced paper.
What is really important for me is the electrochemical concepts in lithium ion batteries which doesn't allow the anode material to experience anodic overpotential vs its OCV. We can discuss on this topic. Please take a llok at Figure 1 of this paper as well. How could that possible for anode electrode to get 4 V vs Li/Li+ without experiencing anodic dissolution and disintegration.
Thanks
No-win: Q: "How could that possible for anode electrode to get 4 V vs Li/Li+ without experiencing anodic dissolution and disintegration.", mainly, due to Cu (-substrate) anodic dissolution.
Also, the abnormal (cell's) site of the RE (2ndLi) in this ref., and the very strong bias/es[1] creates huge tracks inside perplexities due to out of equilibrium (cell's) dynamics.
So, the graph[2] should be reexamined.
1. using, in your ref. '[8].pdf', 3 different high i-values,
2. this graph, 'overdischarge test of LIB.jpg', is, actually, a "fabricated figure".
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