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Vanadium pentoxide (V 2 O 5 ) has been extensively used as the cathode material for lithium-ion batteries (LIBs). But the chemical dissolution of V 2 O 5 in the electrolyte greatly restrains its electrochemical performance, especially cycling stability. In the present research, polypyrrole (PPy)-coated V 2 O 5 yolk−shell nanospheres (V 2 O 5 @PPy) were synthesized by a simple solvothermal method in combination with the vapor deposition method. The density functional theory (DFT) analysis demonstrated that the PPy layer formed by oxidative polymerization manifested hydrophobicity and shielded the trace amount of water on electrode materials. Moreover, the polymerization process induced a gradient distribution of oxygen vacancies in the material and facilitated the rapid transfer of charges. The yolk−shell structure provided sufficient spaces to alleviate the structure change of electrode materials during lithiation/delithiation and inhibited the structural degradation. Hence, V 2 O 5 @PPy displayed an excellent cycling performance by improving the electrical conductivity and suppressing the chemical dissolution of V 2 O 5 . When the discharge current densities were 1 A g −1 and 5 A g −1 , an ultralong cycling life of 1000 cycles (discharge specific capacity of 133.3 mAh g −1 ) and 5000 cycles (discharge specific capacity of 121 mAh g −1 ) was obtained in the voltage range of 2.5−4.0 V, respectively.

Nanoporous tungsten oxide (WO3) films have been widely applied in gasochromic and electrochromic windows due to their high hydrogen diffusion ability. However, a high annealing temperature is required to remove the organic template, which may also collapse the structure of the functional materials. As a photocatalyst, the electron holes in the valence band of WO3 generated after UV irradiation exhibit a high oxidation activity and can degrade organic materials. Here, nanoporous WO3 films with pore sizes ranging from 10 to 16 nm were prepared through sol–gel methods with poly­(ethylene glycol)-block-poly­(propylene glycol)-block-poly­(ethylene glycol) (P123) as an organic template and WO3 as a photocatalytic assistant after UV radiation treatment in a low-temperature environment. After UV degradation treatment, P123 was suitably removed, and the orthorhombic structure of the WO3 film was notably preserved. WO3 could promote the ultraviolet (UV) degradation process of templates. The prepared WO3 nanoporous film exhibited a good thermal stability, fast coloring/bleaching and an excellent cycling performance after annealing at 200 °C. Thermal insulation experiments verified that gasochromic windows with nanoporous films achieve a high energy-saving potential.