Scalable Cable-Type Lithium-Ion Supercapacitors with High Loading Mass and Promotional Volumetric Energy Density

Due to the impressive flexibility and stitchability, one-dimensional (1D) power storage devices are promising in facilitating devices assembly and provide highly efficient power sources for textile-based wearable electronics. Current 1D devices are restricted by the lower loading mass and limited contact area between electrodes, which leads to dissatisfactory electrochemical properties and difficulty to meet the energy requirement. In this study, we employ carbon nanotubes macro film (CMF) as a current collector film to load active materials for fabricating cable-type lithium-ion supercapacitors (CLiSc). Active materials (Li₄Ti₅O₁₂ as anode and active carbon as cathode) are anchored on the surface of CMF and then the electrodes are coupled on the surface of carbon nanotubes fiber (CNF). As a result, the electrodes achieve a high loading mass of 13.6 mg/cm² for cathode and 8.84 mg/cm² for anode, and the obtained CLiSc exhibits high capacity and excellent durability, especially a satisfactory volumetric energy density of 14.1 mWh/cm³, which is higher than all of the previously reported supercapacitors. The inspiring results are attributed to the anchored effect and large contact area of electrodes, which deliver rapid electronic/ionic transport kinetics. Furthermore, the CLiSc can be normally powered in various kinds of actual service conditions, such as bent, knot, weave, and serial or parallel integration. In addition, the CLiSc could be expediently connected with electronics in the same side by the CNF, which is convenient for the connection with electronic devices. This novel CLiSc is expected to be used in wearable electronic devices, and the pathbreaking research will open a new view to design and prepare state-of-the-art power storage devices for synchronizing the exploding development of electronics.