Fig. 2

Ampacity of the CNT–Cu fibers. a Logarithmic scale of the I–V characteristics obtained from the ampacity measurements for the pristine CNT fiber and CNT–Cu microfibers. The inset shows the linear scale data. b Ampacities of the CNT–Cu fibers (solid circles) and effective ampacities through the Cu conduction paths (open hexagons) of various samples. The ampacity of each sample was estimated by a calculation using the maximum current data recorded in Fig. 4a and the cross-sectional areas obtained from the cross-sectional SEM images. The estimation of the effective ampacity is described in the text. The red star denotes the ampacity measured for a pure Cu wire. c Electrical conductivities of different samples at 300 K (solid circles) and effective conductivities of the Cu conduction paths (open hexagons). The electrical conductivity measured for a pure Cu wire is denoted by a red star