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Atomic layer deposition (ALD) has been gaining in popularity as a powerful deposition technique and have been shown to be a promising interfacial engineering method to boost the electrochemical performance of supercapacitors, bridging the gap in energy density. In that regard, we developed an ALD technique to deposit titanium dioxide (TiO2) nanofilms onto porous activated carbon (AC) electrodes. This study focused on the critical aspects of the ALD process that were still unexplored by previous relevant works, including the effects of precursor pulse duration and film thickness on the complex porous structures of AC. In particular, these comprehensive investigations pave the way towards uniform distribution and excellent conformity of the TiO2 nanofilms across the AC surface. Moreover, the deposited films were found to be amorphous and resulted in increased amounts of oxygen-containing surface functional groups. The enhanced electrochemical behavior from the TiO2 nanofilms were found to be optimal at 60 ALD cycles with an estimated film thickness of 2.3 nm. The assembled supercapacitor device coated with this ALD technique exhibited higher specific capacitance compared to the bare AC. The key findings of this work provide the foundation of an effective strategy using ALD for fabricating new electrode materials for high-performance supercapacitors. 

This paper summarizes the results of one of the first comprehensive laboratory studies that was conducted to evaluate the effects of adding different contents of recycled polyethylene terephthalate (rPETE) as a modifier to an asphalt binder on the rheological and mechanical properties of the modified binder as well as on the agglomeration behavior between the rPETE and asphalt binder at a multiscale level. The high-temperature and low-temperature performances of the modified binder were investigated at the macro-scale and compared with those of the unmodified binder using dynamic shear rheometer (DSR) and bending-beam rheometer (BBR) rheological tests, as well as asphalt binder cracking device (ABCD) testing. The nano-scale evaluation of the binder properties, including the surface roughness, bonding energy, and reduced modulus, was accomplished using atomic force microscopy (AFM). The results indicated that the addition of rPETE enhanced the high- and intermediate-temperature rheological properties of the modified PG 64-22 binder. The low-temperature rheological properties and resistance to cracking decreased slightly with increasing rPETE content in the asphalt binder. However, this reduction was not remarkable when adding 4%, 8%, and 10% rPETE contents. The asphalt binder modified with 4% rPETE had a low-temperature grade of −22, similar to that of the unmodified binder, indicating that 4% rPETE can be added to the binder to improve its high- and intermediate-temperature properties without reducing its resistance to low-temperature damage. The AFM tapping-mode results indicated that the inclusion of rPETE in the asphalt binder improved the stiffness properties of the modified binder as compared with those of the control asphalt binder. In addition, the rPETE-modified binders showed rougher surfaces than the control binder. The addition of rPETE to the binder increased the values of the reduced modulus and bonding energy compared with those of the control binder.