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.

Designing acid-stable oxygen evolution reaction (OER) electrocatalysts with low noble-metal content to facilitate the sluggish kinetics is crucial for sustaining green hydrogen generation. Herein, we developed a rutile-structured ruthenium–manganese solid solution oxide with oxygen vacancies (Mn_0.73Ru_0.27O_2−δ) by using an electron-feeding modulation strategy to stabilize the catalyst structure and accelerate the OER kinetics. Due to the optimal electronic structure and enhanced electrical conductivity, the Mn_0.73Ru_0.27O_2−δ catalyst displayed a low overpotential of 208 mV to reach 10 mA cm⁻² current density in 0.5 M H₂SO₄ electrolyte, outperforming the benchmark RuO₂ and most previously reported noble-metal based OER catalysts. Experimental characterization verified that the electron transfer occurred from Ru to Mn atoms with the bridging O atom, which was further enhanced with the existence of oxygen vacancies. Therefore, the center Ru active sites in an electron-deficient state is favorable for bonding with active oxygen intermediates. Meanwhile, theoretical calculations revealed that the simultaneous incorporation of Mn components and O vacancies significantly decreased the anti-bonding spin states of Ru's d-orbitals, which modulated the adsorption and desorption energy barriers of elementary reactions on the active Ru sites, thus boosting the overall OER kinetics.

Ice aggregation is a global challenge, especially for cold regions. In this article, a novel anti-icing hybrid material synthesized by grafting fluorinated polymer chains to silica nanoparticles via surface-initiated activators generated by electron transfer atom transfer radical polymerization (SI-AGET ATRP) was proposed. It showed such properties as controllable molecular design, wonderful thermal stability and high superhydrophobicity. Most importantly, it exhibited excellent anti-icing properties by using coatings with different wettabilities that varied from hydrophilic to superhydrophobic. Its large static water contact angle (WCA, 170.3°) and small contact angle hysteresis (CAH, <3°) can promote the removal of droplets efficiently. A new characterization method, DSC, was used to test the crystallization point of water and its results demonstrated that the crystallization point can be depressed to a large extent (6.82 °C). The low temperature WCA showed that it can postpone the freezing time from 196 s to 10 054 s which indicates the surface can prevent ice formation well, especially with the help of external forces. The mechanisms were discussed based on physicochemical properties, heterogeneous nucleation theory and heat transfer theory. According to the present study, it is reasonable to predict that the organic–inorganic hybrid superhydrophobic coating will be a prospective anti-icing candidate for various applications such as wind turbine blades, power lines and aircraft.

The multifunctional superhydrophobic surfaces incorporated with Fe ₃ O ₄ exhibit excellent anti-icing and active deicing properties.

A superhydrophobic surface with anti-icing performance has been the focus of research, but few studies have reported the effective and low cost strategy that met the requirements under overcooled conditions. In this article, the fluorinated sol–gel colloid coatings were simply prepared via hydrolytic condensation of nanosilica sol, methyltriethoxysilane (MTES) and 3-[(perfluorohexylsulfonyl)amino]propyltriethoxysilane (HFTES). The multi scale morphology and chemical composition of the artificial surfaces were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The influence of the surface roughness structure and fluorinated groups on the wettability and freezing delay time of the colloid surface under overcooled conditions were explored. As the HFTES content was higher than 6 wt%, the prepared colloid surface showed excellent superhydropobicity with a contact angle (CA) of about 166° at room temperature. The CA gradually reduced with the decrease of the temperature. Only the samples with high HFTES contents (above 30 wt%) exhibited special superhydrophobic and anti-icing properties under freeze temperature. Besides the surface roughness structure, the high fluoride enrichment on the surface plays a major role in the superhydrophobic and anti-icing properties under overcooled conditions.