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• Alkalic heptaphenyltrisilanol sodium salt polyhedral oligomeric silsesquioxane was utilized as catalyst and silicon source to obtain novel boron-silicon hybrid phenolic resin (BPOSSPR). • BPOSSPR composites possesses excellent thermal, mechanical, insulation, and ablation resistance properties. • The relationships of the oxidation and ablation behaviors for the thermal protection BPOSSPR under extreme environments were illustrated. • The mechanisms for thermal responses, oxidation, ceramic formation, and ablation of these thermal protection materials were provided. To further enhance the ablation resistance properties of thermosetting phenolic resin matrix composites, in this work, bifunctional alkalic heptaphenyltrisilanol sodium salt polyhedral oligomeric silsesquioxane was utilized to catalyze the synthesis of boron phenolic resin and provide silicon source to obtain boron-silicon hybrid phenolic resin (BPOSSPR) with excellent ablative resistance. BPOSSPR possesses a low curing activation energy (101.4 kJ/mol) and excellent thermal properties (initial decomposition temperature was 453.0 °C and char yield at 1000 °C was 72.7%). The mechanical and thermal insulation properties of carbon fiber reinforced BPOSSPR composites (CF/BPOSSPR) and high silica fiber reinforced BPOSSPR composites (HSF/BPOSSPR) are significantly enhanced. The linear ablation rate and mass ablation rate of CF/BPOSSPR are as low as 0.003 mm/s and 0.0354 g/s; those of HSF/BPOSSPR are 0.119 mm/s and 0.0264 g/s. The ablation-resistance mechanism of BPOSSPR composites is mainly due to the formation of ceramic thermal barrier layers under high temperature conditions, such as B 2 O 3 , SiO 2 , borosilicate glass, SiC, which might play an effective role in protecting against heat flow erosion. As a result of these excellent properties, the innovative heat shielding BPOSSPR composites could offer the ability to tolerate harsher environment in future aerospace applications. [ABSTRACT FROM AUTHOR]

The homogeneous hybridization of organic–inorganic-metal elements in 3D aerogel was achieved by an expeditious method.The aerogel tightly integrates excellent thermal insulation (49.6 mW m−1K−1), ablative resistance, mechanical strength, and superhydrophobic properties.The ablated carbon aerogel combines notable electromagnetic interference shielding properties (31.6 dB) and load-carrying properties (272.8 kN·m kg−1).

Nanomaterials with tunnel structures are extremely attractive to be used for electrode materials in electrochemical energy storage devices. Tunnel-structured Ti-doped Na4Mn9O18nanoparticles (TNMO-NPs) were synthesized by a facile and high-production method of the solid-state reaction with a high-energy ball-milling process. As electrode materials in the supercapacitor cell, the as-synthesized TNMO-NPs exhibit a high specific capacity of 284.93 mA h g–1(0.57 mA h cm–2/1025.75 F g–1). A superior rate capability with a decay of 36% is achieved by increasing the scan rates from 2 to 25 mV s–1. To further explore the storage mechanism of Ti-doped Na4Mn9O18materials, density functional theory (DFT) calculations were used to calculate the activation energy for the ion immigration in the electrode, and the results show that the minimum ion diffusion barrier energy is 0.272 eV, indicating that the sodium ions could insert into the system easily. Through the scan-rate-dependent cyclic voltammetry analysis, the capacity value indicates a mixed charge storage of capacitive behavior and Na+intercalation progress. A maximum energy density of 77.81 W h kg–1at a power density of 125 W kg–1is achieved, and a high energy density of 54.79 W h kg–1is maintained even at an ultrahigh power density of 3750 W kg–1. The TNMO-NP supercapacitors show excellent flexibility at various bent (0–180°) states. The capacitive performance of the TNMO-NPs makes them promising cathode materials for flexible supercapacitors with high specific capacities and high energy densities.

The Na2Ti3O7·2H2O nanobelts (Na-TNBs) with layered structure have been prepared by simple hydrothermal method. The carbon modified Na-TNBs (C/Na-TNBs) supercapacitor has been encapsulated by the flexible and stretching PDMS (poly-dimethylsiloxane), which has flexible and stretching property. The capacitance of the device can attain 459.71Fg−1at scan rate of 25mV/S and energy density of 33.2Whkg−1at power density 478Wkg−1and power density of 2.13kWkg−1at energy density 25.36Whkg−1. The retention of specific capacitance remains 74.3% after 6000 cycles at high current value of 35mA. Three supercapacitors in series can light 100 green color commercial light emitting diodes (LEDs) for about 10min. All these results indicate that the C/Na-TNBs nanomaterial could provide the potential application in high performance supercapacitor.

To enhance the ablation resistance of phenolic-based composites, Zr4+was coordinated with Ph-O-of phenolic resin (PR) to obtain the Zr chelated hybrid PR (ZrPR), which reduces the Ph-OH content of PR and provides metal-organic chelated point for the cured system, ensuring higher thermal stability of PR. The initial decomposition temperature and thermal residual rate at 1000°C of ZrPR was increased from 305.0°C to 57.6% to 405.2°C and 65.5%. Carbon fiber (CF) reinforced ZrPR (CF/ZrPR) composites had flexural and interlaminar shear strengths of 496.0 and 34.0 MPa, 20.2 and 33.3% greater than unmodified composites (CF/PR). Thermal conductivity, linear and mass ablation rate of CF/ZrPR composites were 1.198 W/(m·k), 0.023 mm/s and 0.0607 g/s, respectively, which were 16.7, 50.0 and 10.6% lower than CF/PR composites. The surface ceramic layer with ZrO2and ZrC phase composition formed from ZrPR in extreme heat can produce an insulating effect to shield the inner material from catastrophic ablation. This research might lead to the development of new and more practical ablation resistant composites for aerospace applications.