Highly conductive cellulose network/polyaniline (PANI) composites are successfully formed using chemical fractionation of solid wood followed by in situ polymerization of aniline monomers in the purified wood. The increased porosity of the wood caused by the fractionation process enables the uniform deposition of PANI particles in the microstructure of the material, resulting in a high electrical conductivity of up to 36.79 S cm−1, and a high weight gain rate of up to 143%. The interaction between PANI and the cellulose microfibril network leads to a decreased crystallinity of the composites. The electrode prepared from the cellulose network/PANI composites exhibits promising gravimetric specific capacitances of up to 218.75 F g−1 and areal specific capacitances of up to 0.41 F cm−2, and it can be assembled into all‐solid‐state supercapacitors with favorable energy storage performance, which may be attributed to the larger surface area, higher PANI content of the electrode, and the positive effect of the cellular structure of the cellulose network on electron transport. The present process can preserve the naturally hierarchical structure of wood and impart a promising conductivity to the composites, and it provides a promising way to produce hierarchical biomass‐based electronic materials for high‐performance storage field.

Front Cover: In article number 1900112 by Fangchao Cheng and co‐workers, cellulose network/polyaniline composites with hierarchical porous nanostructure of wood are successfully prepared, which exhibit high conductivity and promising specific capacitance when used as electrode materials in all‐solid‐state supercapacitors.

Low-cost flexible thermoelectric (TE) films with excellent cooling performance are critical for the in-plane heat dissipation application based on the TE film refrigeration technology. In this work, a flexible film epoxy/Bi0.5Sb1.5Te3 is developed by the incorporation of ferromagnetic Co nanoparticles to improve the electrical transport and cooling performance. The magnetic properties and microstructures clearly indicate that part of Co nanoparticles in situ reacts with Te from Bi0.5Sb1.5Te3 to form CoTe2, as well as BiTe′ antisite defects. The electric conductivity is greatly enhanced because of the increased carrier density, while a large Seebeck coefficient is well maintained because of the extra magnetic scattering. The power factor of the flexible film with 0.2 wt % Co nanoparticles reached 2.28 mW·m–1·K–2 at 300 K, increased by 34% compared to the epoxy/Bi0.5Sb1.5Te3 film. The maximum cooling temperature difference is 1.5 times higher compared with the epoxy/Bi0.5Sb1.5Te3 film. This work provides a general method to improve the electrothermal conversion performance of BiSbTe-based flexible films through in situ reaction.

Improving the thermoelectric (TE) performance of Bi 2 Te 3 -based flexible films remains a huge challenge. Herein, high-performance Ni/epoxy/Bi 0.5 Sb 1.5 Te 3 magnetic flexible TE films are prepared by incorporating Ni nanoparticles (Ni-NPs). Atomic-resolution STEM investigation demonstrates that Te vacancies induced by the orientation reaction between Ni-NPs and Te from Bi 0.5 Sb 1.5 Te 3 trigger the presence of negatively charged ( ) ′′′ ′′′ V V V V B Bi i S Sb b and ( ( ) ) ′ ′ B Bi i S Sb b T Te e T Te e anti-site defects and atomic-sized electric field in the magnetic flexible TE films and further cause the acceleration movement and hopping migration of carriers. The transport measurements indicate an increased carrier concentration due to the anti-site defects, while the significant increase of carrier mobility originates from the acceleration movement of carriers. The magnetic scattering and hopping migration of carriers are responsible for maintaining large Seebeck coefficient. As compared to epoxy/Bi 0.5 Sb 1.5 Te 3 flexible TE film, the maximum power factor of the magnetic flexible TE film with 0.1% Ni-NPs reaches 2.74 mW m −1 K −2 at 300 K and increases by 61%, while the cooling temperature difference increases by 250%.

Herein, we demonstrate a structure-enabled strategy to construct an ultrastable, high-performance, ultraflexible all-in-one supercapacitor with a one-piece wood cellulose network/polyaniline/multiwalled carbon nanotube composite as both the electrodes and the separator....