(Invited) Predication of High-Rate and Low-Temperature Battery Performance By Ion Transport Obtained from Impedance Using Symmetric Cells

Abstract

The expansion of lithium-ion battery (LIB) usage from small applications such as portable electronic devices to large applications such as electric vehicles and stationary power supply1 necessitates the improvement of high-rate LIB performance especially at the low-temperature region, due to the growing frequency of outside use.2 , 3 The major reason of LIB performance degradation during low-temperature operation is considered to be non-uniform reaction occurrence, which is due to a decrease in Li ion transport for charge compensation inside porous electrode during charge/discharge. In order to quantitatively determine this Li ion transport at the LiNiO2-based positive electrodes with various loading weight, porosity, and conductive carbon ratio, electrochemical impedance spectroscopy using symmetric cells (EIS-SC)4-9 was performed. In this presentation, the feasibility of the obtained ion transport was investigated in terms of parameters of predicting high-rate and low-temperature battery performance.10 The high-rate and low-temperature cycle performance of LIB was performed using a cylindrical battery composed of LiNiO2-based positive/graphite negative electrodes with LiPF6-based electrolyte at a rate of 5C corresponding 0.2 h charging/discharging and a temperature of 0 °C. The capacity retention was calculated from the capacity after 200 cycles relative to the initial capacity at a temperature of 25 °C. The electrochemical cell for impedance measurement consists of two uncharged LiNiO2-based positive electrodes via a separator containing the same Li-based electrolyte. The Nyquist plots obtained are straight line with a slop of 45° and vertical straight lines with respect to the real axis in the high and low-frequency regions, respectively, indicative of typical blocking behavior in porous electrode. Using the Nyquist plots and transmission line mode theory to investigate electrochemical processes in porous electrodes,11 the ionic resistances inside the porous positive electrodes (R ion) were quantitatively determined as ion transport parameter. The reciprocal of ionic resistance (R ion −1) for all electrodes of various configurations exhibits nicely positively correlation with capacity retention of low-temperature (0 °C) battery cycling; that is, the capacity retention of the low-temperature cycle test increases as R ion −1 increases. This result suggested that for a porous electrode, high ionic resistance (which corresponds to low ion transport) results in reaction non-uniformity, which causes the deterioration of high-rate and low-temperature cycling lifetime.Regarding the conventional cycle-test procedure for practical LIBs, there are problems of material and time consumption since it requires long testing after producing many large batteries. In this work, we subject symmetrical cells with small-sized and real-life electrodes to impedance analysis, and electrochemically quantify ion transport in practical porous electrodes employing a simple protocol that can be used to estimate high-rate and low-temperature LIB performance in a short time without finally producing many large batteries. Therefore, this criterion allows us the possibility of simple prediction for such high-rate and low-temperature LIB performance, and therefore contributes to the realization of an energy storage system that meets the demands for high-rate and low-temperature performances such as fast-charging in the future.References S. Chu and A. Majumdar, Nature, 488, 294-303 (2012). M.-T. F. Rodrigues, G. Babu, H. Gullapalli, K. Kalaga, F. N. Sayed, K. Kato, J. Joyner and P. M. Ajayan, Nat. Energy, 2, 17108 (2017). R. Schmuch, R. Wagner, G. Hörpel, T. Placke and M. Winter, Nat. Energy, 3, 267-278 (2018). N. Ogihara, Y. Itou, S. Kawauchi, C. Okuda, Y. Takeuchi and Y. Ukyo, Meeting s, MA2012-02, 723 (2012). N. Ogihara, S. Kawauchi, C. Okuda, Y. Itou, Y. Takeuchi and Y. Ukyo, J. Electrochem. Soc., 159, A1034-A1039 (2012). N. Ogiahra, Y. Itou, S. Kawauchi, T. Kobayashi and Y. Takeuchi, Meeting s, MA2013-02, 947 (2013). Y. Itou, N. Ogihara, C. Okuda, T. Sasaki, H. Nakano, T. Kobayashi and Y. Takeuchi, Meeting s, MA2014-04, 611 (2014). N. Ogihara, Y. Itou, T. Sasaki and Y. Takeuchi, J. Phys. Chem. C, 119, 4612-4619 (2015). Y. Itou, N. Ogihara and S. Kawauchi, J. Phys. Chem. C, 124, 5559-5564 (2020). N. Ogihara, Y. Itou and S. Kawauchi, J. Phys. Chem. Lett., 10, 5013-5018 (2019). R. de Levie, Electrochim. Acta, 9, 1231-1245 (1964).