Porous carbons with advanced nanostructures and volumetric performance are particularly attractive and essential for miniature supercapacitors to access high energy densities and capacitances, both for portable electronics and massive electrical equipments. However, the electrochemical performances and the pore structure are closely bound up, both restricted by pore volume and pore density. Herein, the wood slice (~0.7 mm) with the periodic porous structure is chosen as the basic framework with rich macropores and the graphene nanotube array (GNTA) with mesopores is used as an intermediate structure in situ synthesized to form the substructure in macropores; therefore, the biomass and nanotube array together construct a porous carbon with hierarchical pores and large surface area. On this basis, Cu‐Co oxides are coated on the surface of the pores, to increase the capacitance of electrodes for supercapacitor applications. Because of the GNTA, the specific surface area increases from 38.2 to 1086.0 m² g⁻¹, which is quite helpful for the deposition of Cu‐Co oxide nanosheets and effectively alleviates their typical self‐stacking phenomenon. Meanwhile, the GNTA creates multiscale pores that served as channels for the rapid electron transfer and ion shuttling; as a result, the resistance obviously induces and capacitance increased by 131% (from 323.4 to 747.5 mF cm⁻²). For the assembled all‐wood asymmetric supercapacitor, the specific capacitance is 151.2 F g⁻¹ (1 A g⁻¹), the energy density is 53.8 Wh kg⁻¹ with a power density of 900 W kg⁻¹, and the specific capacitance remains extremely stable during the cycling. Our work provides a practical structure–design strategy for high‐performance supercapacitors.

To synergistically improve the energy storage capacity and mechanical flexibility of wearable energy storage devices, a facile method to realize intrinsic stretchable AgNWs-bridged MXene porous electrode, especially for enabling the fabrication of microwearable supercapacitors with high resolution, is developed in this work. The continuous AgNWs network provides more abundant and lower resistivity electron and ion transport channels, while improving the stretchability of MXene electrodes intrinsically to accommodate bending and stretching strains. The AgNWs-bridged MXene porous electrode exhibits a capacitance of 287 $\text{F}\cdot\text{cm}^{-\text{3}}$ when works as a negative electrode, excellent cycle stability (more than 92% retention after 5000 cycles), and out-standing intrinsically stretchability (96.3% retention after stretching strain of 50%). Even after 100 cycles of 20% stretching deformation, the capacitance retention rate is still above 97%, which proves the stability of the AgNWs-bridged MXene porous electrode and shows great potential in wearable and flexible electronics.

With the development of high-speed and high-temperature equipment, thermal barrier materials are facing increasingly harsh service environments. The addition of YAG to Y₂Hf₂O₇ has been proposed in order to improve its long-term high-temperature performance. In this work, Y₂Hf₂O₇/Y₃Al₅O₁₂ composite powders were synthesized by combustion synthesis with urea, glycine, EDTA, citric acid, and glucose as fuels, while hafnium tetrachloride, yttrium nitrate hexahydrate, and aluminum nitrate nonahydrate were used as raw materials. The effects of fuels on the morphology and phase composition of synthetic powders were studied. Chemical reaction kinetic parameters were established by the Kissinger, Augis and Bennett, and Mahadevan methods. Y₂Hf₂O₇ and Y₃Al₅O₁₂ are the main components in the powders synthesized with urea as fuel, while YAlO₃ and Y₂Hf₂O₇ are the main phases with the other fuels. SEM and TEM analysis reveal that the powders prepared by the solution combustion method exhibit a typical porous morphology. When urea is used as fuel, the powders show a uniform elemental distribution, distinct ceramic grain crystallization, clear grain boundaries, and a uniform distribution of alternating grains. Compared to several other fuels, urea is more suitable for the preparation of Y₂Hf₂O₇/Y₃Al₅O₁₂ composite powders. In the process of preparing powders with urea, the activation energies for the combustion reaction calculated using the three methods are 100.579, 104.864, and 109.148 kJ·mol⁻¹, while the activation energies related to crystal formation are 120.397, 125.001, and 129.600 kJ·mol⁻¹, respectively.