Fig. 2: Li-driven stress monitoring in Li || Si cells with liquid electrolyte.
a Time-resolved voltage profile (top) and Δλ (bottom, left) evolution from the FBG sensor of a Li | (LP30+FEC)| Si cell with liquid electrolyte with the FBG placed at the interface between the Si-based electrode and the electrolyte contained in the porous separator. The discharge capacity (bottom, right) is also presented at the end of each lithiation. After each discharge and charge, 6 h of OCV were defined, shadowed in gray and yellow, respectively. b, c Comparison of the first and second cycle for micro-Si and nano-Si electrodes, respectively. The dQ/dV plots together with the Δσ evolution from a FBG sensor located on top of the corresponding silicon electrodes are presented. Schemes of the sequential steps (i) porosity filling, (ii) electrode thickening, and (iii) particles pulverization are shown in the figure. The porosity of the nano-Si electrode and micro-Si electrode was 51% and 75%, respectively. d, e Comparison of the sixth to the tenth cycle for micro-Si and nano-Si electrodes, respectively. The dQ/dV plots together with the Δσ evolution is shown. f Galvanostatic curves of the 12th to 18th cycles for the nano-Si cells with different cut-off voltages together with the corresponding g Δσmax for the different capacities achieved. The cells were cycled in a 25 °C oven at a C-rate of C/30 (120 mA g−1) for micro-Si and C/10 (360 mA g−1) for nano-Si to better compare the cycling conditions in terms of efficient particle surface current density.
