EIS Study on the Electrode-Separator Interface Lamination

Abstract

This paper presents a comprehensive study of the influences of lamination at both electrode-separator interfaces of lithium-ion batteries consisting of LiNi1/3Mn1/3Co1/3O2 cathodes and graphite anodes. Typically, electrode-separator lamination shows a reduced capacity fade at fast-charging cycles. To study this behavior in detail, the anode and cathode were laminated separately to the separator and compared to the fully laminated and non-laminated state in single-cell format. The impedance of the cells was measured at different states of charge and during the cycling test up to 1500 fast-charging cycles. Lamination on the cathode interface clearly shows an initial decrease in the surface resistance with no correlation to aging effects along cycling, while lamination on both electrode-separator interfaces reduces the growth of the surface resistance along cycling. Lamination only on the anode-separator interface shows up to be sufficient to maintain the enhanced fast-charging capability for 1500 cycles, what we prove to arise from a significant reduction in growth of the solid electrolyte interface.

SEI Growth Impacts of Lamination, Formation and Cycling in Lithium Ion Batteries

“…Nyquist plots of datasets and fitting curves are shown in Figure 6. All Nyquist datasets reveal similar structure of the EIS response, correlating to our previous studies [39]. The highest frequency domains were dominated by inductive effects, resulting from the EIS setup environment.…”

“…Applying the electrode-separator lamination technique previous to cycling again proves as a valid modification for the reduction of capacity fading phenomena as reported in our previous studies [38,39], and improves the cell performance at the 2C formation rate. As the SEI growth phenomena were shown to act as the main aging effect tuned by lamination at fast-charging protocols, the given cycling data indicate similar aging effects driving the modified cell performance at fast-formation.…”

“…Batteries 2020, 6, x FOR PEER REVIEW 3 of 15 especially on the fast-charging capability of graphite NMC 111 cells [38,39]. The lowered capacity losses along fast-charging cycles were shown to arise from a significant reduction in SEI growth upon lamination at the anode-separator interphase [39].…”

“…During operation, carbon-based anodes undergo reduction potentials of typical electrolyte components [7] like ethylene carbonate (EC), dimethyl carbonate (DMC), ethylmethyl carbonate (EMC), diethyl carbonate (DEC) and LiPF 6 , while typical composite cathodes exceed potentials inducing polymerization electrochemical aspects remain mostly unclear. Recent studies on lamination revealed benefits especially on the fast-charging capability of graphite NMC 111 cells [38,39]. The lowered capacity losses along fast-charging cycles were shown to arise from a significant reduction in SEI growth upon lamination at the anode-separator interphase [39].…”

“…Recent studies on lamination revealed benefits especially on the fast-charging capability of graphite NMC 111 cells [38,39]. The lowered capacity losses along fast-charging cycles were shown to arise from a significant reduction in SEI growth upon lamination at the anode-separator interphase [39]. The lamination technique was also shown to tune the C-rate stability of graphite-NMC 111 cells similar to application of external cell pressure during operation [38].…”