In order to investigate the basic mechanical properties and stress strain relationship model for bamboo scrimber manufactured based on a new technique, a large quantities of experiments have been carried out. Based on the analysis of the test results, the following conclusions can be drawn. Two main typical failure modes were classified for bamboo scrimber specimens both under tension parallel to grain and tension perpendicular to grain. Brittle failure happened for all tensile tests. The slope values for the elastic stages have bigger discreteness compared with those for the specimens under tensile parallel to grain. The failure modes for bamboo scrimber specimens under compression parallel to grain could be divided into four. Only one main failure mode happened both for the bending specimens and the shear specimens. With the COV values of 28.64 and 25.72 respectively, the values for the strength and elastic modulus under tensile perpendicular to grain have the largest discreteness for bamboo scrimber. From the point of CHV values, the relationship among the mechanical parameters for bamboo scrimber were proposed based on the test results. Compared with other green building materials, bamboo scrimber manufactured based on a new technique has better mechanical performance and could be used in construction area. Three stress strain relationship models which are four-linear model, quadratic function model, and cubic function model were proposed for bamboo scrimber specimens manufactured based on a new technique. The latter two models gives better prediction for stress strain relationship in elastic plastic stage.

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The development of hollow and porous materials is essential for effective energy storage and conversion owing to their facile transport of electrons and ions. Herein, through a facile low-temperature thermal decomposition reaction of ZIF-67 crystals, hollow Co 3 O 4 nanocages composed of numerous nanoparticles with a porous structure are prepared. These hollow and porous Co 3 O 4 nanocages (Co 3 O 4 HPCs) possess a pore size distribution between 20 and 60 nm and a large Brunauer−Emmett−Teller surface area of 211.79 m 2 g −1 . Benefitting from the large surface area, a maximum specific capacitance of 140.0 F g −1 can be calculated. Furthermore, the assembled Co 3 O 4 HPCs//activated carbon hybrid supercapacitor can deliver an energy density of 19.8 W h kg −1 and 97.3% capacitance retention during 5000 cycles. As a result of good electrochemical performance of these Co 3 O 4 HPCs, they can be a promising electrode for supercapacitors.

Hollow nanostructures with enlarged surface areas are highly attractive electrode materials for supercapacitors. In this work, the size-dependent synthesis of hollow Co3O4 nanocubes via a facile ionic exchange reaction between Co-Fe Prussian blue analogues (PBAs) and alkali solution is reported. By adjusting the concentration of sodium citrate to control the reaction kinetics during nucleation and growth, four different sizes of Co-Fe PBAs were synthesized. It was also found that a Co-Fe PBA of about 140 nm can be easily converted into a well-defined internal hollow structure, while Co-Fe PBAs with smaller or larger sizes are challenged in generating a hollow structure. Benefitting from the inner voids and thin shell architecture, the derived hollow Co3O4 nanocubes exhibit a high specific capacity of 296.6C cm−2 at 2 mA cm−2, and a rate capability of 64.5% when the current density is increased to 60 mA cm−2. Furthermore, a hybrid supercapacitor (HSC) was fabricated with hollow Co3O4 nanocubes as the cathode and activated carbon as the anode, respectively. The HSC provided a maximum energy density of 14.1 Wh kg−1 at 464.7 W kg−1. Moreover, it retained the excellent cycling stability of 85.7% of the original capacity over 5000 continuous charging and discharging processes.

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