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Moore's law predicts the performance of integrated circuit doubles every two years, lasting for more than five decades. However, the improvements of the performance of energy density in batteries lag far behind that. In addition, the poor flexibility, insufficient-energy density, and complexity of incorporation into wearable electronics remain considerable challenges for current battery technology. Herein, a lithium-ion cable battery is invented, which is insensitive to deformation due to its use of carbon nanotube (CNT) woven macrofilms as the charge collectors. An ultrahigh-tap density of 10 mg cm of the electrodes can be obtained, which leads to an extremely high-energy density of 215 mWh cm . The value is approximately seven times than that of the highest performance reported previously. In addition, the battery displays very stable rate performance and lower internal resistance than conventional lithium-ion batteries using metal charge collectors. Moreover, it demonstrates excellent convenience for connecting electronics as a new strategy is applied, in which both electrodes can be integrated into one end by a CNT macrorope. Such an ultrahigh-energy density lithium-ion cable battery provides a feasible way to power wearable electronics with commercial viability.

High specific surface area and reasonable pore-size distribution are conducive to promote the energy density and power density of carbon based supercapacitors. Nevertheless, the permeability of electrolyte is a prerequisite condition for surface storage charge and the ion diffusion in multiscale pores. Therefore, improving the electrolyte penetration/absorption is particularly important. Herein, we reported a novel three-dimensional porous ultrathin carbon nanosheet (3DPAC) with considerable electrolyte penetration/absorption property, which was proven by experiment and theory. The 3DPAC was prepared from abundant biomass waste wood dust via hydrothermal and carbonized treatment and characterized with ultrathin nanosheets, abundant porous structure, and rich N, O dopant. This unique three-dimensional and hierarchical porous structure leads to robust conduction of electrons and the penetration/absorption of electrolyte ions, which endow the 3DPAC with approved electrochemical properties. The supercapacitor based 3DPAC shows satisfying energy density (79.4 Wh/kg) and power density (5.1 kW/kg), and impressive cyclic stability with 94.6% after 5000 charge/discharge processes. More amazing, the soft-packaged supercapacitor presents stable electrochemical behaviors at multiple folding states and low pressure environment. Therefore, this meaningful research will open a brand-new direction to devise and prepare state-of-art porous carbon materials for high-performance supercapacitors applied in complex environments.

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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.