The rapid development of portable/wearable electronics proposes new demands for energy storage devices, which are flexibility, smart functions and long-time outdoor operation. Supercapacitors (SCs) show great potential in portable/wearable applications, and the recently developed flexible, smart and self-sustainable supercapacitors greatly meet the above demands. In these supercapacitors, conductive polymers (CPs) are widely applied due to their high flexibility, conductivity, pseudo-capacitance, smart characteristics and moderate preparation conditions. Herein, we’d like to introduce the CP-based flexible, smart and self-sustainable supercapacitors for portable/wearable electronics. This review first summarizes the flexible SCs based on CPs and their composites with carbon materials and metal compounds. The smart supercapacitors, i.e., electrochromic, electrochemical actuated, stretchable, self-healing and stimuli-sensitive ones, are then presented. The self-sustainable SCs which integrate SC units with energy-harvesting units in one compact configuration are also introduced. The last section highlights some current challenges and future perspectives of this thriving field.

The development of flexible wearable triboelectric nanogenerators (TENGs) has attracted great interest in the application of self-powered multifunctional electronic devices. However, the practical application of textile-based TENGs still faces numerous obstacles, such as low-output performance, high-cost, and complex structure. Herein, we reported a novel wearable TENG based on nickel–copper bimetallic hydroxide nanowrinkles (NC-TENG) to harvest the mechanical energy from human motion. The nickel–copper bimetallic hydroxide and polytetrafluoroethylene (PTFE) film form a triboelectric pair, which was grown on carbon cloth via a hydrothermal method. Owing to the nano-scale surface topography of nickel–copper bimetallic hydroxide nanowrinkles, the NC-TENG may achieve high-output performance. The maximum instantaneous V_oc and I_sc of NC-TENG (size: 1 cm × 1 cm) arrived at 328 V and 36.15 μA, respectively. Besides, the maximum output power density achieved was 1.323 mW cm⁻², which is 13 times the electrical output of the TENG based on the carbon cloth and PTFE film. This study demonstrates the promising potential of a novel TENG for wearable electronics.

Self‐powered sensing technologies are increasingly sought for intelligent and autonomous marine environmental monitoring. A Faraday cage‐enabled triboelectric nanogenerator (FC‐TENG) is developed by incorporating a FeCoCrNiAl alloy powder layer, enabling efficient harvesting of low‐frequency mechanical energy. The quasi‐enclosed conductive architecture mimics a Faraday cage, effectively confining electrostatic charges and suppressing edge‐induced dissipation, thereby enhancing charge retention. Compared to single‐metal triboelectric layers, the FC‐TENG exhibits 4.86‐, 3.57‐, and 2.76‐fold increases in open‐circuit voltage (V_OC, 1276.27 V), short‐circuit current (I_SC, 63.69 μA), and transferred charge (Q_SC, 29.55 nC), respectively. Its hydrophobic surface further ensures environmental robustness and stable output under humid conditions. With an optimized load resistance of 60 MΩ, the FC‐TENG device achieves a peak power of ~4.08 mW and reliably powers LED arrays and environmental sensors, while enabling efficient energy storage across a wide frequency range. Furthermore, a wave‐driven FC‐TENG system integrated with wireless communication and visual feedback modules enables real‐time marine motion monitoring without external power. This work introduces the Faraday cage–inspired triboelectric device based on microspherical alloy powder, offering enhanced charge retention, humidity tolerance, and dual‐mode functionality in power generation and marine wave sensing. The proposed strategy provides a robust and scalable architecture for future self‐powered systems operating in harsh environments.