I am attempting to construct a Li ion battery in a split test cell configuration. I have been using copper coated with graphite powder as the anode and aluminum coated with the same graphite powder for cathode. The electrolyte I am using is created from making 1.0 M Lithium bis-trifluoromethanesulfonlyimide in 1,3-dioxolane and 1,2-dimethoxyethane (1:1 by volume) with 0.5% LiNO3 in a glovebox. This electrolyte method comes from a modified form of electrolyte made in (https://iopscience.iop.org/article/10.1149/1.3148721/pdf) and found on (https://www.cheaptubes.com/resources/graphene-battery-users-guide/). I am using polypropylene as separator material. I am using a Landt battery tester for charge and discharge testing. I have been testing between 1mA and 5mA charge and discharge cycles, with a safety cutoff voltage of 5V. I also allow the cell to rest for 1 hour. When I tried testing the cell it appears to be shorting somehow. Some tests have shot quickly above the 5V limit and others simply keep constant current charge, but is failing to increase the voltage of the cell, and when taken off charge it quickly drops to zero volts for the OCV(open circuit voltage). Any suggestions as to what is hindering my cell from operating?
Hello there,
You said you are attempting to construct a 'Li-ion battery'. Correct me if I am wrong, but where is the lithium host in your electrode? My understanding is the aluminum electrode should be coated with the lithium doped metal oxide like LCO or (L)NMC, (L)NCA so that the lithium ion moves from one electrode to another during respective charge and discharge cycles. Hence the 'lithiation' and 'de-lithiation' ?
Again correct me if I'm missing an obvious here.
Thank you for your reply Roshan Mangal Bhattarai. I had believed that the available lithium ions would come from the electrolyte from either the Lithium bis-trifluoromethanesulfonlyimide or the lithium nitrate in solution. I dripped the solution onto each side of the separator in order to make contact with the electrodes. Could my cell not be undergoing lithiation due to not having available lithium metal oxide?
Lithium bis(trifluoromethanesulfonyl)imide and lithium nitrate are salts that support lithium ion movements (and not the electron) between anode and cathode. I haven't seen anyone using them as a replacement of a lithium containing cathode material.
My suggestion would be to use lithium metal itself (if available of course) or lithium metal oxides as a cathode and graphite as a anode and 1M LiPF6 dissolved in ethylene carbonate/dimethyl carbonate (EC: DMC=1:1 v/v) as an electrolyte (this is the most commonly used electrolyte for LIB). LiNO3 is mostly used in LIS batteries to improve the efficiency of the cell and is not necessary in your case. although you can try it and observe the difference.
Thank you Roshan Mangal Bhattarai . I have began testing with a lithium metal cathode, and am still using my graphite coated copper current collector. As such the cells are now able to charge and discharge. I am also awaiting an order of LiPF6, so thank you for your recommendation.
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