Ultrahigh‐Energy Density Lithium‐Ion Cable Battery Based on the Carbon‐Nanotube Woven Macrofilms

Abstract 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 −2 of the electrodes can be obtained, which leads to an extremely high‐energy density of 215 mWh cm −3 . 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.