Fig. 3.

Characterization of composite electrodes. a Bar chart comparing the electrical conductivity comparison of various electrodes. The dashed lines are the electrical conductivity of MX-C and MX-N freestanding films. b Electrical conductivity change of the nSi/MX-C and Gr-Si/MX-C electrodes upon bending, as shown in the insets. The almost constant conductivity values indicate the robust nature of our Si/MXene electrodes. c, d Comparison of the mechanical properties of various electrodes. c Representative stress-strain curves for various electrodes. d Top: tensile toughness (i.e. tensile energy density required to break film) plotted as a function of strain at break (%). Bottom: tensile strength plotted as a function of Young’s modulus. The mechanical properties indicate that the MXene nanosheets confer mechanical reinforcement component, resulting in much enhanced toughness and tensile strength