Recently, to ameliorate the forthcoming energy crisis, sustainable energy conversion and storage devices have been extensively investigated. Potassium-ion batteries (KIBs) have aroused widespread attention in these very active research applications due to their earth abundance and similar low redox potential compared to Li-ion batteries (LIBs). It is critical to develop electrode materials with large ion diffusion channels and robust structures for long cycling performance in KIBs. Metal coordination materials, including metal-organic frameworks, Prussian blue, and Prussian blue analogue, as well as their composites and derivatives, are known as promising materials for high-performance KIBs due to their open frameworks, large interstitial voids, functionality and tailorability. In this review, we give an overview of the recent advances on the application of metal coordination materials in KIBs. In addition, the methods to enhance their K-ion storage properties are summarized and discussed, such as morphology engineering, doping, as well as compositing with other materials. Ultimately, some prospects for future research of metal coordination materials for KIBs are also proposed.

The effects of water on the wear resistance of 3 µm thick sputtered gold films on silicon substrate using contact AFM and a scanning nanoindenter was investigated. In performing wear tests on gold samples in the presence of water, a significant increase in depth of the wear area was observed compared to the same tests performed in the ambient atmosphere (~55% humidity). These results were obtained using Hysitron Triboindenter on areas of 10x10 µm 2 and an Atomic Force Microscope on areas of 1x1 µm 2 . Nanowear tests were preformed using silicon nitride cantilevers on the AFM and diamond Berkovich or blunt conical tips on the Hysitron. Normal loads used were 2 µN and 10 µN, respectively. Tests performed in the ambient atmosphere resulted in a slightly reduced surface roughness, while a much higher wear rate was observed in the wear tests performed in water. Additionally, gold surface ripples formed under certain scanning conditions, in water for the Hysitron Triboindenter and in ambient atmosphere for the AFM. Nanoscale stick slip is being investigated as a possible explanation to the rippling phenomenon, and single scan line tests provide valuable information about the mechanisms and progression of the nanoscale wear.

Nanoindentation and photoluminescence (PL) studies were performed on hydrogenated boron carbon nitride thin films deposited using radio frequency magnetron sputtering. Dual target sputtering from B4C and BN targets was used to deposit films. The variation in the composition of films was studied using energy-dispersive X-ray spectroscopy. The influence of hydrogen gas and substrate temperature on the mechanical properties was investigated using nanoindentation measurements. Photoluminescence studies were performed on films deposited under varying hydrogen content and different deposition temperatures. The films deposited in this study exhibited hardness of 6–22 GPa and Young’s modulus of 125–140 GPa. PL spectra demonstrated two prominent emission peaks around 499 nm and 602 nm for the deposited films. Increasing the hydrogen gas ratio in the films induced PL peak shifts to longer wavelengths. Emission spectra shifted to long wavelength with increasing substrate temperature. The emission peak position shifted from 499 nm to 544 nm and from 602 nm to 655 nm as a function of substrate temperature. For the first time, BCNH based thin films PL behavior at low temperature (77 K) has been characterized in this study. The BCNH thin films show a rare phenomenon of negative thermal quenching of emission.

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A bstractCarbon ®ducial marks are formed during thin-®lm local delamination processes induced either by superlayer indentation forming circular blisters, or by residual stress relief through telephone cord blister formation. Hydrocarbons are sucked into the crack tip during the delamination process, outlining the cracktip-opening angle, which can be used to back calculate thin-®lm adhesion using either elastic or plastic analyses presented here. Fiducial marks have been observed in two di erent thin-®lm systems, namely Cu/SiO2 and TiWxNy/ GaAs. Cu/SiO2 delamination blisters have been cross-sectioned using the focused-ion-beam method, and high-resolution scanning electron microscopy of the cross-sections revealed crack renucleation ahead of the original crack tip. This is attributed to the stress redistribution process due to the dislocation shielding mechanism. At stress intensity levels of 0.33 MPa m 1/2 , it is found that four emitted dislocations can account for crack arrest, with renucleation of 100 nm sized nanocracks dependent on the antishielding stresses.