Electrochemical Noise is a benign method that uses no excitation. The technique is based on simple measurement of current or voltage, without any perturbations. Originally developed exclusively for monitoring stochastic corrosion, it is currently under development for studying effects in batteries.
Use of metallic lithium provides increased voltage and energy density, it is therefore very common for primary batteries. However, issues with controlling the deposition hinder the use of metallic lithium in rechargeable cells. Though there is significant progress in getting metallic lithium in rechargeable cells, large scale commercial implementation is yet to be achieved.
We are presenting studies on monitoring the voltage noise of batteries as a way of monitoring the state of metallic lithium in a real-time, operando and non-perturbing manner. There is no doubt that the potential and the part of it deemed noise contains invaluable information regarding the details of the underlying phenomena inside the battery. We have already published on the details of the noise associated with uneven discharge of metallic lithium (Karaoglu G, Uzundal CB and Ulgut B; J. Electrochem. Soc. 167 130534). We showed unequivocally that the increased noise in voltage is associated with the different surfaces or metallic lithium and the current collector. In the current contribution, we will be presenting noise studies associated with the surface formations during charging of a metallic lithium anode. As the deposition leads to various kinds of surfaces both chemically and morphologically, the electrochemical potential measured on the overall system oscillates between the potentials caused by individual surfaces.
Our studies are ultimately geared towards an online real-time sensor that can follow the status of the meallic lithium anode throughout the use of a given cell. This would enable smart use of metallic lithium through judicious monitoring and use algorithm design.