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There has been keen interest for years in the research of all-solid-state transmittance-type electrochromic (EC) devices due to their various applications especially in “smart windows”. However, limited durability remains a severe issue.

The visualization of the microstructure change and of the depth of lithium transport inside a monolithic ElectroChromic Device (ECD) is realized using an innovative combined approach of Focused Ion Beam (FIB), Secondary Ion Mass Spectrometry (SIMS) and Glow Discharge Optical Emission Spectroscopy (GDOES). The electrochemical and optical properties of the all-thin-film inorganic ECD glass/ITO/WO3/LiTaO3/NiO/ITO, deposited by magnetron sputtering, are measured by cycling voltammetry and in situ transmittance analysis up to 11 270 cycles. A significant degradation corresponding to a decrease in the capacity of 71% after 2500 cycles and of 94% after 11 270 cycles is reported. The depth resolved microstructure evolution within the device, investigated by cross-sectional cutting with FIB, points out a progressive densification of the NiO layer upon cycling. The existence of irreversible Li ion trapping in NiO is illustrated through the comparison of the compositional distribution of the device after various cycles 0, 100, 1000, 5000 and 11 270. SIMS and GDOES depth profiles confirm an increase in the trapped Li content in NiO as the number of cycles increases. Therefore, the combination of lithium trapping and apparent morphological densification evolution in NiO is believed to account for the degradation of the ECD properties upon long term cycling of the ECD.

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Great interest has been drawn to the electrochromism demonstrated by inorganic materials, leading to various applications including smart windows and displays. NiO, as a cheap material, shows anodic electrochromism and is highly suitable for device applications in conjunction with W0 3 , but its strong optical absorbanoe has been largely overlooked. Herein, improved electrochromic properties in particular in short wavelengths was achieved by co doping of Mg and Li in NiO:(Ll, Mg) thin films grown using RF sputtering. Secondary Ion Mass Spectroscopy technique in combination with X ray Photoelectron Spectroscopy characterization provides direct evidence of the introduction of Mg as well as Li in the film Whatever the Li and Mg content, X Ray Diffraction and Raman spectroscopy studies only bring out the NiO face centered cubic rock sait structure. Electrochemical cycling shows pronounced anodic electro chromism for NiO:(Ll, Mg) thin films. Inorganic ail solid state monolithic multilayered devices are traditionally composed of a pair of electrodes with NiO and WOJ separated by Li containing electrolyte such as LiTa0 3 or LlNb0 3 sputtered from expensive but low efficient ceramic targets. Based on optimal NiO:(Ll, Mg) films, large switchable electrochromism both in visible (-58%) and ultraviolet band (-50%) is reconciled in electrochromic device Glass/ITO/NiO:(Li, Mg)(ra20sfW0 3 /ITO. The co doping of NiO with Mg and Li is capable of simultaneously widening the gap and avoiding the use of Li containing elec trolyte, through NiO pre lithiation. We believe the new, low cost approach would provide references with respect to practical applications desired for their successful commercial mass production.

To the best of our knowledge, very few works have been done on the continuous real-time monitoring of proton exchange membrane fuel cells (PEMFCs) membrane degradation based on fluoride-specific electrochemical microsensors. PEMFCs are eco-smart energy sources for efficient transportation but experience variable degradation rates that wear the membrane electrode assembly (MEA), a critical component of the fuel cell's functionality. Current market options lack specific diagnostics and legitimate indication of when exactly the membrane must be replaced. As such, this work focused on manufacturing a sensor for measuring MEA degradation in real-time by selectively monitoring fluoride concentration in effluent water, a signature PEMFCs degradation status, through functionalized LaF3:(Au nanoparticle) thin films (~60 nm). The sensor’s exceptional specificity/sensitivity has been achieved in real-time at a sub 10 ppb level, optimized through spin-coating deposition and post-annealing process. Its multimodal readout has been achieved and studied through the characterizations of open circuit potential, cyclic voltammetry, chronoamperometry and differential pulse voltammetry, revealing a consistent linear decrease of 15.7 mA/cm2 at 0 ppb to 10.2 mA/cm2, while also maintaining its low-cost, small size, and robustness.