The emergence of stretchable electronic devices has attracted intensive attention. However, most of the existing stretchable electronic devices can generally be stretched only in one specific direction and show limited specific capacitance and energy density. Here, we report a stretchable isotropic buckled carbon nanotube (CNT) film, which is used as electrodes for supercapacitors with low sheet resistance, high omnidirectional stretchability, and electro-mechanical stability under repeated stretching. After acid treatment of the CNT film followed by electrochemical deposition of polyaniline (PANI), the resulting isotropic buckled acid treated CNT@PANI electrode exhibits high specific capacitance of 1147.12 mF cm(-2) at 10 mV s(-1). The supercapacitor possesses high energy density from 31.56 to 50.98 μWh cm(-2) and corresponding power density changing from 2.294 to 28.404 mW cm(-2) at the scan rate from 10 to 200 mV s(-1). Also, the supercapacitor can sustain an omnidirectional strain of 200%, which is twice the maximum strain of biaxially stretchable supercapacitors based on CNT assemblies reported in the literature. Moreover, the capacitive performance is even enhanced to 1160.43-1230.61 mF cm(-2) during uniaxial, biaxial, and omnidirectional elongations.

Thick electrode with high-areal-capacity is a practical and promising strategy to increase the energy density of batteries, but development toward thick electrode is limited by the electrochemical performance, mechanical properties, and manufacturing approaches. In this work, we overcome these limitations and report an ultrathick electrode structure, called fiberaligned thick or FAT electrode, which offers a novel electrode design and a scalable manufacturing strategy for high-areal-capacity battery electrodes. The FAT electrode uses aligned carbon fibers to construct a through-thickness fiber-aligned electrode structure with features of high electrode material loading, low tortuosity, high electrical and thermal conductivity, and good compression property. The low tortuosity of FAT electrode enables fast electrolyte infusion and rapid electron/ion transport, exhibiting a higher capacity retention and lower charge transfer resistance than conventional slurry-casted thick electrode design.

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Diabetes adversely impacts many organ systems including the skeleton. Clinical trials have revealed a startling elevation in fracture risk in diabetic patients. Bone fractures can be life threatening: nearly 1 in 6 hip fracture patients die within one year. Because physical exercise is proven to improve bone properties and reduce fracture risk in non-diabetic subjects, we tested its efficacy in type 1 diabetes. We hypothesized that diabetic bone's response to anabolic mechanical loading would be attenuated, partially due to impaired mechanosensing of osteocytes under hyperglycemia. Heterozygous C57BL/6-Ins2Akita/J (Akita) male and female diabetic mice and their age- and gender-matched wild-type (WT) C57BL/6J controls (7-month-old, N=5-7 mice/group) were subjected to unilateral axial ulnar loading with a peak strain of 3500 με at 2Hz and 3 min/day for 5 days. The Akita female mice, which exhibited a relatively normal body weight and a mild 40% elevation of blood glucose level, responded with increased bone formation (+6.5% in Ct.B.Ar, and 4 to 36-fold increase in Ec.BFR/BS and Ps.BFR/BS), and the loading effects, in terms of changes of static and dynamic indices, did not differ between Akita and WT females (p≥0.1). However, loading-induced anabolic effects were greatly diminished in Akita males, which exhibited reduced body weight, severe hyperglycemia (+230%), diminished bone formation (ΔCt.B.Ar: 0.003 vs. 0.030 mm2, p=0.005), and suppressed periosteal bone appositions (ΔPs.BFR/BS, p=0.02). Hyperglycemia (25mM glucose) was further found to impair the flow-induced intracellular calcium signaling in MLO-Y4 osteocytes, and significantly inhibited the flow-induced downstream responses including reduction in apoptosis and sRANKL secretion and PGE2 release. These results, along with previous findings showing adverse effects of hyperglycemia on osteoblasts and mesenchymal stem cells, suggest that failure to maintain normal glucose levels may impair bone's responses to mechanical loading in diabetics.

This paper presents an investigation of the potential to use aligned discontinuous carbon fiber dry prepregs as electrodes in structural supercapacitors (SSCs). The high fiber-matrix interfacial bonding of the structural composite was achieved by adopting a solid polymer electrolyte, consisting of poly(vinylidene), lithium triflate, and epoxy. Processing of the SSC was carried out via dip-coating of the polymer electrolyte and then cured using a vacuum bag. The electrochemical performance of the SSCs was measured before and after mechanical loading. The microstructures of the SSCs as-fabricated and damaged under flexural loading were identified by μ-CT imaging. An SSC with a specific capacitance of 0.128 mF/cm 2 (11.62 mF/g), a flexural strength of 47.49 MPa, and a flexural modulus of 8.48 GPa has been achieved, demonstrating significant improvements in mechanical properties over those of SSCs based on woven carbon fiber fabric-based electrodes. The mechanical behavior of the supercapacitors was evaluated by both quasi-static and cyclic flexural loading tests. The excellent electrochemical stability of the supercapacitors was validated by a capacitance retention of above 96% under galvanostatic charge−discharge cycling tests. The knowledge gained in this work will benefit future research in the optimization of SSC performance.