Revisiting Surface Modification of Graphite: Dual-Layer Coating for High-Performance Lithium Battery Anode Materials.

Surface modification of electrode active materials has garnered considerable attention as a facile way to meet stringent requirements of advanced lithium-ion batteries. Here, we demonstrated a new coating strategy based on dual layers comprising antimony-doped tin oxide (ATO) nanoparticles and carbon. The ATO nanoparticles are synthesized via a hydrothermal method and act as electronically conductive/electrochemically active materials. The as-synthesized ATO nanoparticles are introduced on natural graphite along with citric acid used as a carbon precursor. After carbonization, the carbon/ATO-decorated natural graphite (c/ATO-NG) is produced. In the (carbon/ATO) dual-layer coating, the ATO nanoparticles coupled with the carbon layer exhibit unprecedented synergistic effects. The resultant c/ATO-NG anode materials display significant improvements in capacity (530 mA h g(-1) ), cycling retention (capacity retention of 98.1 % after 50 cycles at a rate of C/5), and low electrode swelling (volume expansion of 38 % after 100 cycles) which outperform that of typical graphite materials. Furthermore, a full-cell consisting of a c/ATO-NG anode and an LiNi0.5 Mn1.5 O4 cathode presents excellent cycle retention (capacity retention of >80 % after 100 cycles). We envision that the dual-layer coating concept proposed herein opens a new route toward high-performance anode materials for lithium-ion batteries.

A facile route for growth of CNTs on Si@hard carbon for conductive agent incorporating anodes for lithium-ion batteries.

Conductive agent incorporating Si anodes consisting of directly grown carbon nanotubes on hard carbon encapsulating Si nanoparticles were prepared by a one-pot chemical vapour deposition process. Owing to this fabulous structure, Si-based anodes exhibit excellent cycle retention and rate capability with a high-mass-loading of 3.5 mg cm(-2).

Novel design of ultra-fast Si anodes for Li-ion batteries: crystalline Si@amorphous Si encapsulating hard carbon.

Nanocrystalline Si (c-Si) dispersed in amorphous Si (a-Si) encapsulating hard carbon (HC) has been synthesized as an anode material for fast chargeable lithium-ion batteries. The HC derived from natural polysaccharide was coated by a thin a-Si layer through chemical vapour deposition (CVD) using silane (SiH4) as a precursor gas. The HC@c-Si@a-Si anodes showed an excellent cycle retention of 97.8% even after 200 cycles at a 1 C discharge/charge rate. Furthermore, a high capacity retention of ∼54% of its initial reversible capacity at 0.2 C rate was obtained at a high discharge/charge rate of 5 C. Moreover, the LiCoO2/HC@c-Si@a-Si full-cell showed excellent rate capability and very stable long-term cycle. Even at a rate of 10 C discharge/charge, the capacity retention of the LiCoO2/HC@c-Si@a-Si full-cell was 50.8% of its capacity at a rate of 1 C discharge/charge and showed a superior cycle retention of 80% after 160 cycles at a rate of 1 C discharge/charge.

Guided bone regeneration using cyanoacrylate-combined calcium phosphate in a dehiscence defect: a histologic study in dogs.

PURPOSE: This study evaluated the effects of cyanoacrylate-combined calcium phosphate (CCP) as a candidate for a barrier membrane substitute in guided bone regeneration and the space maintenance capability of CCP placed in a dehiscence defect model. MATERIALS AND METHODS: Six standardized dehiscence defects (5 × 3 mm, height × width) around dental implants were created on unilateral edentulous ridges in 5 dogs, where each defect was treated with sham surgery, biphasic calcium phosphate (BCP), CCP, barrier membrane (MEM), BCP + MEM, and CCP + MEM. The animals were sacrificed after an 8-week healing interval for histologic and histometric analyses. RESULTS: The BCP and CCP sites showed increased bone formation compared with the control sites, although incomplete defect resolution occurred; bone regeneration heights (area) averaged 3.52 ± 0.69 mm (4.94 ± 2.59 mm(2)), 3.51 ± 0.16 mm (4.10 ± 1.99 mm(2)), and 1.53 ± 0.42 mm (1.01 ± 0.74 mm(2)) for the BCP, CCP, and control sites, respectively. All the MEM sites showed more bone formation compared with the sites that received the same biomaterials without a MEM, and the BCP + MEM and CCP + MEM sites showed extensive bone formation within the defect and on top of the implant; the bone regeneration heights (area) averaged 3.96 ± 2.86 mm (12.46 ± 11.61 mm(2)), 5.45 ± 0.25 mm (11.63 ± 1.97 mm(2)), and 2.62 ± 0.27 mm (3.43 ± 0.98 mm(2)) for the BCP + MEM, CCP + MEM, and MEM sites, respectively. CONCLUSIONS: CCP can be a good scaffold for supporting an MEM as opposed to acting as a substitute for the MEM in guided bone regeneration.

Chondrocyte viability in press-fit cryopreserved osteochondral allografts.

The viability of chondrocytes in press-fit glycerol-preserved osteochondral allografts was compared to that in fresh autografts, after transplantation into load-bearing and non-load-bearing sites in mature sheep stifle joints. We used macroscopic grading, tonometer pen indentation testing, histology, sulfate uptake and viability as determined by confocal-microscopy to assess cartilage condition. Despite there being no statistical differences between macroscopic appearance and tonometer testing of all grafts, confocal microscopy and histology demonstrated a positive effect of load-bearing placement on cryopreserved osteochondral allografts. Allografts transplanted into load-bearing sites demonstrated superior confocal microscopy-measured chondrocyte viability (77%+/-17%SD) than those transplanted into non-load-bearing sites (25%+/-2%). Load-bearing effect was not seen in autografts (78%+/-15%), and was comparable in adjacent cartilage (83%+/-9%). Similarly, load-bearing allografts demonstrated histological scoring closer to that of autografts and adjacent cartilage, all of which fared significantly better than non-load-bearing allografts. Load-bearing allografts had a greater amount of fibrocartilage than autografts or adjacent cartilage but less fibrocartilage than non-load-bearing allografts. Both autografts and allografts had non-significant increases in metabolism compared to adjacent cartilage as measured by sulfate-uptake. Load-bearing placement improved chondrocyte viability of glycerol cryopreserved osteochondral allograft following a press-fit implantation.