A general method for preparing nano-sized metal oxide nanoparticles with highly disordered crystal structure and their processing into stable aqueous dispersions is presented. With these nanoparticles as building blocks, a series of nanoparticles@reduced graphene oxide (rGO) composite aerogels are fabricated and directly used as high-power anodes for lithium-ion hybrid supercapacitors (Li-HSCs). To clarify the effect of the degree of disorder, control samples of crystalline nanoparticles with similar particle size are prepared. The results indicate that the structurally disordered samples show a significantly enhanced electrochemical performance compared to the crystalline counterparts. In particular, structurally disordered Ni FeO @rGO delivers a capacity of 388 mAh g at 5 A g, which is 6 times that of the crystalline sample. Disordered Ni FeO @rGO is taken as an example to study the reasons for the enhanced performance. Compared with the crystalline sample, density functional theory calculations reveal a smaller volume expansion during Li insertion for the structurally disordered Ni FeO nanoparticles, and they are found to exhibit larger pseudocapacitive effects. Combined with an activated carbon (AC) cathode, full-cell tests of the lithium-ion hybrid supercapacitors are performed, demonstrating that the structurally disordered metal oxide nanoparticles@rGO||AC hybrid systems deliver high energy and power densities within the voltage range of 1.0-4.0 V. These results indicate that structurally disordered nanomaterials might be interesting candidates for exploring high-power anodes for Li-HSCs.

Overall structural modification, integrating coating and doping, was developed to enhance the structural stability and Li+ transport kinetics in a layered Ni-rich cathode, which significantly improves the electrochemical performance at high voltage.

Insulin is considered to be a classical central regulator of energy homeostasis. Recently, the effect of insulin on bone has gained a lot of attention, but little attention has been paid to the application in bone tissue engineering. In this study, porous nanohydroxyapatite/collagen (nHAC) scaffolds incorporating poly lactic-co-glycolic acid (PLGA) particles were successfully developed as an insulin delivery platform for bone regeneration. Bioactive insulin was successfully released from the PLGA particles within the scaffold, and the size of the particles as well as the release kinetics of the insulin could be efficiently controlled through Shirasu porous glass premix membrane emulsification technology. It was indicated that the nHAC/PLGA composite scaffolds possessed favorable mechanical and structural properties for cell adhesion and proliferation, as well as the differentiation into osteoblasts. It was also demonstrated that the nHAC/PLGA scaffolds implanted into a rabbit critical-size mandible defect possessed tissue compatibility and higher bone restoration capacity compared with the defects that were filled with or without nHAC scaffolds. Furthermore, the in vivo results showed that the nHAC/PLGA scaffolds which incorporated insulin-loaded microspheres with a size of 1.61 μm significantly accelerated bone healing compared with two other composite scaffolds. Our study indicated that the local insulin released at the optimal time could substantially and reproducibly improve bone repair.

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The effects of lignin chemical structures on the quality of lignin-based carbon fibers are still not clear. For this reason, we address the challenge by using a simple acid precipitation method to separate and purify lignin and study the effects of physicochemical characteristics of fractionated lignin on the properties of lignin-based CFs. The precipitation carried out by sequential acidification at different pH levels (10, 8, 6, 4, and 2) is indeed effective in obtaining fractionated lignin samples with different chemical structures, including molecular weights, units’ composition ratios, and polydispersity indexes (PDIs). All the fractionated lignin samples are respectively blended with polyacrylonitrile at the ratio of 1:1 (w/w) and electro-spun into fibers. Results suggest that a fractionated lignin sample with a large molecular weight, low PDI, and strong thermal stability can produce carbon fibers with excellent performance, such as good spinnability, high crystallization, and mechanical strength.

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