Flexible, Stackable, and Fully Active Thick Electrode with Scalable 3D Topology Braid Structure Enables Supercontinuous Electron/Ion Transport.

Abstract

Thick electrode design is critical for achieving high energy/power density storage. However, it remains a huge challenge to design a fully-active thick electrode with supercontinuous electron/ion transport channels by a cost-effective method. Herein, a flexible, stackable, and fully-active, fully-microporous carbon cloth (FMCC) cathode is developed from cotton cloth by a facile strategy for lithium-ion capacitors (LICs). Fully microporous structure achieves a large specific surface area while retaining a self-supporting structure. The bi-directional woven hollow fiber bundle structure achieves supercontinuous ion/electron transport. Significantly, the FMCC can be flexibly stacked in multiple layers to form a 3D topological network structure, achieving a high-performance thick electrode design. Consequently, the 5-layer FMCC delivers ultrahigh area-specific capacity of 1.53 mA h cm^-2 even at 1 A g^-1 with almost undiminished mass-specific capacity compared to single-layer FMCC. Furthermore, a 4.9 V LIC is assembled based on a carbon cloth cathode/anode with a thick electrode design, realizing an excellent energy/power density. Assembled flexible LIC delivers stable power output even under bending/cutting conditions due to the unique electrode structure. In addition, the charge/discharge mechanism and structure-activity relationship of the FMCC are revealed in detail, which provides a constructive view for designing flexible, fully-active thick electrodes.