Ambient Air Conditions Research Articles

Dopant-Free Hole-Transporting Material Based on Poly(2,7-(9,9-bis(N,N-di-p-methoxylphenylamine)-4-phenyl))-fluorene for High-Performance Air-Processed Inverted Perovskite Solar Cells.

It is a great challenge to develop low-cost and dopant-free polymer hole-transporting materials (HTM) for PSCs, especially for efficient air-processed inverted (p-i-n) planar PSCs. A new homopolymer HTM, poly(2,7-(9,9-bis(N,N-di-p-methoxylphenyl amine)-4-phenyl))-fluorene (denoted as PFTPA), with appropriate photo-electrochemical, opto-electronic and thermal stability, was designed and synthesized in two steps to meet this challenge. By employing PFTPA as dopant-free hole-transport layer in air-processed inverted PSCs, a champion power conversion efficiency (PCE) of up to 16.82% (0.1 cm2) was achieved, much superior to that of commercial HTM PEDOT:PSS (13.8%) under the same conditions. Such a superiority is attributed to the well-aligned energy levels, improved morphology, and efficient hole-transporting, as well as hole-extraction characteristics at the perovskite/HTM interface. In particular, these PFTPA-based PSCs fabricated in the air atmosphere maintain a long-term stability of 91% under ambient air conditions for 1000 h. Finally, PFTPA as the dopant-free HTM was also fabricated the slot-die coated perovskite device through the same fabrication condition, and a maximum PCE of 13.84% was obtained. Our study demonstrated that the low-cost and facile homopolymer PFTPA as the dopant-free HTM are potential candidates for large-scale production perovskite solar cell.

Optimized Placement of Frost-Measuring Sensors in Heat Exchangers via Image Processing of Frost Formation Pattern.

Heat exchangers (HXs) play a critical role in maintaining human thermal comfort and ensuring product safety and quality in various industries. However, the formation of frost on HX surfaces during cooling operations can significantly impact their performance and energy efficiency. Traditional defrosting methods primarily rely on time-based control of heaters or HX operation, overlooking the actual frost formation pattern across the surface. This pattern is influenced by ambient air conditions (humidity and temperature) and surface temperature variations. To address this issue, frost formation sensors can be strategically placed within the HX. However, the non-uniform frost pattern poses challenges in sensor placement. This study proposes an optimized sensor placement approach using computer vision and image processing techniques to analyze the frost formation pattern. Through creating a frost formation map and evaluating various sensor locations, frost detection can be optimized to control defrosting operations with higher accuracy, thereby enhancing the thermal performance and energy efficiency of HXs. The results demonstrate the effectiveness of the proposed method in accurately detecting and monitoring frost formation, providing valuable insights for sensor placement optimization. This approach presents significant potential in enhancing the overall performance and sustainability of the operation of HXs.

Monitoring the Past and Future Trends of Urban Thermal Comfort Conditions Through a New Methodology

Human thermal comfort representing the satisfaction of mind with ambient air conditions has significant effects on socioeconomic activities. Climate change is affecting thermal comfort conditions (TCCs) negatively. Therefore, it is important to estimate their past and future trends to take accurate measures for mitigation and adaptation efforts in especially urban areas. However, it is difficult to calculate TCCs for the future since they are the combined effect of several meteorological parameters on a person outdoor together with her/his own physiological characteristics, which must be evaluated individually. This study is aimed at determining the TCCs trends in the past compared to the present whilst estimating the future conditions using a new methodology in the case of Kayseri city in the Interior Anatolia Region of Turkey. As the result of the study, all the change trends considering temporal and spatial results show that thermal comfort conditions signal warmer and higher heat stress in the past and future trends. This means human thermal sensation ranges (e.g., very cold) have replaced with the next warmer range, and their spatial distribution in percentage has also changed towards warmer. Increase in the prevalence of unfavourable thermal comfort conditions causes the decrease in the liveability indicators in especially urban areas, including serious economic loses based on energy consumption, health care expenses, and efficiency of activities. It is required that both past and expected future trends be considered in the planning and design works to make cities resilient and have higher adaptive capacity to climate change.

Formation of Antifouling Brushes on Various Substrates Using a Melanin-Inspired Initiator Film.

In this study, we developed a substrate-independent initiator film that can undergo surface-initiated polymerization to form an antifouling brush. Inspired by the melanogenesis found in nature, we synthesized a tyrosine-conjugated bromide initiator (Tyr-Br) that contains phenolic amine groups as the dormant coating precursor and α-bromoisobutyryl groups as the initiator. The resultant Tyr-Br was stable under ambient air conditions and underwent melanin-like oxidation only in the presence of tyrosinase to form an initiator film on various substrates. Subsequently, an antifouling polymer brush was formed using air-tolerant activators regenerated by electron transfer for atom transfer radical polymerization (ARGET ATRP) of zwitterionic carboxybetaine. The entire surface coating procedure, including the initiator layer formation and ARGET ATRP, occurred under aqueous conditions and did not require organic solvents or chemical oxidants. Therefore, antifouling polymer brushes can be feasibly formed not only on experimentally preferred substrates (e.g., Au, SiO2, and TiO2) but also on polymeric substrates such as poly(ethylene terephthalate) (PET), cyclic olefin copolymer (COC), and nylon.

An optimal control strategy for ASHP units with a novel dual-fan outdoor coil for evener frosting along airflow direction based on GRNN modelling

It was demonstrated in previous related experimental and modelling studies that an ASHP unit having a novel dual-fan outdoor coil (ASHP / DFOC) can help achieve evener frosting along airflow direction in the outdoor coil, leading to its better operating performances. To enable an ASHP / DFOC unit to efficiently operate at varying ambient conditions, an optimal control strategy for the experimental ASHP / DFOC unit was developed using a Generalized Regression Neural Network (GRNN) modelling approach, which is a variation to radial basis neural networks. A database for developing the GRNN model was established first, and a new coefficient of performance related index, which was the change rate of averaged COP (CRAC) was proposed after analysing the database. Then, based on the developed database and CRAC, a GRNN model was developed and validated, and then used to predict and search the optimal dual-fan operating modes when the experimental ASHP / DFOC unit was operated at different ambient air conditions. Finally, an optimal control strategy for the experimental ASHP / DFOC unit based on those identified optimal dual-fan operating modes was developed and experimentally validated. The experimental results demonstrated that the use of the developed optimal control strategy led to a higher heating efficiency, a longer frosting - defrosting duration and a fewer number of dual-fan switching for the experimental ASHP / DFOC unit, with its averaged COP improved by 9.9 % and 6.8 %, CRAC decreased by 17.1 % and 10.5 %, defrosting frequency reduced by 22.2 % and 12.5 %, and averaged frosting - defrosting duration extended by 32.8 % and 19.4 %, respectively, when compared to the use of traditional single-fan operating mode and a fixed dual-fan operating mode at varying ambient conditions. The study results can help achieve evener frosting of ASHPs with a higher operating efficiency and better feasibility at varying ambient conditions.

Hole-Transport Management Enables 23%-Efficient and Stable Inverted Perovskite Solar Cells with 84% Fill Factor

HighlightsA graded inverted solar cell configuration is developed by hole-transport management aiming to suppress interface defects-induced non-radiative recombination for efficient hole transport.NiOx-based inverted PSCs present a power-conversion-efficiency over 23% with a high fill factor of 0.84 and open-circuit voltage of 1.162 volts, one of the best performances reported so far for 1.56-electron volt bandgap formamidinium-based triple-halide perovskites.Devices show high operational stability over 1,200 h during T90 lifetime measurement under 1-sun illumination in ambient-air conditions.

Nonfullerene Agent Enables Efficient and Stable Tin‐Based Perovskite Solar Cells

Tin‐based perovskites have emerged as the most promising lead‐free perovskite materials due to the characteristics of the environmentally friendly and more suitable bandgap. However, the power conversion efficiency still lags behind the lead perovskite owing to unfavorable defects of the perovskite film and poor interface contact between tin perovskite and electron transporting layers. Herein, an n‐type conjugated nonfullerene molecule, termed IO‐4Cl, is developed for efficient and stable tin perovskite solar cells (TPSCs). The IO‐4Cl possesses electron‐donating functional groups that can enlarge grain size and passivate defect states of perovskite films through Lewis acid–base interactions. Besides, the IO‐4Cl exhibits an appropriate lowest unoccupied molecular orbital level and interface‐modification ability, enabling superior electron extraction and transport ability of TPSCs. More importantly, the hydrophobic characteristic of IO‐4Cl prevents the decomposition of perovskite films under moisture conditions, improving the moisture stability of TPSCs. Consequently, the TPSCs with IO‐4Cl achieve a champion efficiency of 11.49% with an open‐circuit voltage increase of 100 mV, and excellent moisture stability under ambient air condition with 30% relative humidity, without encapsulation. The work provides a new inspiration for the introduction of functional nonfullerene materials to obtain highly efficient and stable TPSCs.

Stable high conversion efficiency of Quasi-2D perovskite solar cells via potassium iodide as additive

Although two-dimensional (2D) perovskite is more stable than three-dimensional (3D) perovskite, its poor film quality and low photoelectric conversion efficiency are still the focuses of researchers. In this article, we introduce a simple and effective method to modify the quasi-2D (BA)2(MA)3Pb4I13 perovskite solar cells by introducing potassium iodide as an additive. We found that the introducing K ion made perovskite film more compact, reduced the number of grain boundaries and regulated the band alignment. Besides, the incorporation of K+ reduced the nonradiative recombination and hysteresis effect of the device. As a result, the power conversion efficiency (PCE) of solar cells increased from initial 13.91% to 16.82% under optimized concentration of 16% (mole ratio compared to N-butyl ammonium iodide BAI). What is more, the device with K+ modification showed excellent environmental stability, which could maintain 95% of their original efficiency after 720 h under ambient air condition, whereas the pristine devices without K+ only keep 53% of their initial efficiency and the thermal stability has also been improved. This result provides a simple and promising method through additive engineering to achieve high PCE and stable quasi-2D perovskite solar cells.

Synthesis in ambient air of LaVxFe1−xO3 compounds by the sol-gel method: Structural and optical studies

In the present study, we successfully synthesized LaVxFe1−xO3 powders following a standard sol-gel protocol under ambient air conditions. This synthesis was made possible thanks to the use of ascorbic acid as a reducing agent. There was no need for a controlled environment or vacuum to prevent vanadium from oxidation. Ascorbic acid has the advantage of helping to adjust the pH of the solution until it turns green, which is an indication of the presence of the V+3 oxidation state. Structural characterization was performed using X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy, while optical bandgap energies were determined using UV-Visible spectrophotometry. The vanadium fraction of 25% vanadium showed tiny, agglomerated nanoparticles with an estimated size of about 30 nm, and a globally orthorhombic structure was obtained. Deeper infrared analyzes were able to highlight a deformed structure of LaFeO3 inside which very few FeO6 octahedra are replaced by deformed VO6 octahedra. Due to these, a bandgap reduction occurred from 2.31 eV to 1.86 eV, proving that the combination of lanthanum ferrite and lanthanum vanadate is a successful strategy to tune the bandgap energy while retaining the orthorhombic structure. Such a combination therefore offers a promising way for the fabrication of devices with a high potential for harvesting and conversion for applications based on solar irradiation.

How to stabilize standard perovskite solar cells to withstand operating conditions under an ambient environment for more than 1000 hours using simple and universal encapsulation

We introduce a simple and universal scalable encapsulation strategy for perovskite solar cells based on thermal vacuum evaporation of MgF2 or MoO3-x capping layer followed by sealing the device with glass and UV-curable polymer. The proposed encapsulation method is beneficial to most of the other known encapsulation approaches being fully harmless to perovskite and transporting layers and processible at room temperature. Vacuum deposition of the capping layer promotes efficient removal of water, oxygen and organic solvent residuals from the device prior to sealing and could be easily performed using standard equipment for metal electrode deposition. The proposed strategy is transferrable to any lab-scale perovskite solar cell prototypes regardless of their geometry and architecture and results in excellent stability of the devices in ambient air and long operating conditions. Upon the 1000 hours stability test at ambient air (30%-60% RH), the cells preserved 92.9% of their initial efficiency on average under 1 Sun illumination at constant maximum power point tracking (MPPT, ISOS-L-1) and over 96% under storage in the dark (ISOS-D-1), thus evidencing for the high effectiveness of the proposed encapsulation approach.

The comparison of wear performances of CP-Ti, Ti6Al4V, Ti45Nb alloys oxidized by anodic oxidation under ambient air and vacuum conditions

The comparison of wear performances of CP-Ti, Ti6Al4V, Ti45Nb alloys oxidized by anodic oxidation under ambient air and vacuum conditions

Fully Methylammonium-Free Stable Formamidinium Lead Iodide Perovskite Solar Cells Processed under Humid Air Conditions.

Fabricating perovskite solar cells (PSCs) in ambient air condition is beneficial for lowering the processing cost and boosting the commercialization. Formamidinium lead iodide (FAPbI3) is an attractive candidate for efficient PSCs; however, it easily suffers from degradation and phase transition in the presence of ambient moisture. Methylammonium (MA) cation is commonly incorporated to stabilize FAPbI3, whereas the residual MA tends to deteriorate the thermal and operational stability. Herein, we report a MA-free strategy to fabricate high-quality α-FAPbI3 films and inverted PSCs under open air conditions with a relative humidity (RH) of 60 ± 10%. The incorporation of phenylethylammonium iodide (PEAI) effectively inhibits the decomposition and phase transition of FAPbI3 during its crystallization in humid air. Accordingly, phase-pure α-FAPbI3 perovskite films with significantly reduced δ-FAPbI3 and PbI2 content are successfully obtained. In addition, introducing PEAI strongly enhances the crystallinity of FAPbI3 perovskite films, thereby yielding enlarged grain sizes and reduced grain boundaries. Defects at the grain boundaries and surface are further passivated by PEAI addition, so that the trap state density is significantly decreased. As a result, the non-radiative recombination is effectively suppressed and the charge carrier transport is promoted. The inverted device optimized with a suitable PEAI concentration exhibits an enhanced power conversion efficiency (PCE) of 17.83%, which significantly surpasses the control device (12.29% PCE). Moreover, the PEAI optimized FAPbI3 PSCs demonstrate strongly improved long-term stability, with nearly 97% PCE maintained after 27-day storage under ambient conditions. This work provides a feasible way to fabricate PSCs in ambient air for promoting their wide range of applications.

Strong Photocurrent from Solution‐Processed Ruddlesden–Popper 2D Perovskite–MoS2 Hybrid Heterojunctions

AbstractThis study reports overall improvement in structural, morphological, and optoelectronic properties of Ruddlesden–Popper (RP) perovskites of type (BA)2(MA)n−1PbnI3n+1 by forming their bulk heterojunction hybrids with few‐layer MoS2 nanoflakes. RP perovskite–MoS2 hybrid thin films have shown significantly improved packing and crystallinity compared to pristine perovskites. The presence of MoS2 at RP perovskite interface has improved the quantum confinement effects and transport of photogenerated charge carriers from perovskite to MoS2, due to suitable conduction band of MoS2 and more number of decay channels. The optoelectronic properties of RP perovskite–MoS2 hybrids are studied for various MoS2 concentrations (4.2–25.6 × 10−3 m) and at optimum concentration (12.8 × 10−3 m) the photodetectors (n = 2, 4) have shown strong, sharp, and highly stable photocurrent response. At 0.0 V bias, the RP perovskite (n = 4) and MoS2 (12.8 × 10−3 m) hybrid‐based photodetectors, prepared without any encapsulation, have shown strong photocurrent density of ≈9.8 µA cm−2 under 1 sun illumination, which is ≈17 times higher compared to the pristine RP perovskites‐based photodetector (0.6 µA cm−2). Further transient photocurrent, performed over 200 cycles for hybrid (n = 4+MoS2) thin film photodetector under laser (λex ≈ 405 nm, ≈630 mW cm−2) illumination and ambient air conditions has shown highly stable photocurrent with only ≈9.6% reduction in the peak photocurrent density.

Neutropenia-related aspergillosis in non-transplant haematological patients hospitalised under ambient air versus purified air conditions.

To reduce the risk of invasive aspergillosis (IA), air purification by high-efficiency particulate air filtration and laminar air flow (HEPA/LAF) is standard of care in allogeneic blood stem cell transplantation. Its use in non-transplant haematological patients is inconsistent. We sought to assess the incidence and outcome of pulmonary IA in non-transplant patients with life-threatening neutropenia by comparing an ambient air hospitalisation period (2008-2011) with a subsequent HEPA/LAF hospitalisation period (2012-2014). We compared 204 consecutive patients with acute myeloid leukaemia, acute lymphoblastic leukaemia or aplastic anaemia completing 534 neutropenia-related hospitalisations under ambient air conditions with 126 such patients completing 437 neutropenia-related hospitalisations under HEPA/LAF conditions. IA was defined using the 2008 EORTC/MSG criteria. Within a 7-year study period, we observed one 'proven', three 'probable' and 73 'possible' IAs, most often during acute leukaemia remission induction. Their frequency rose with increasing duration of life-threatening neutropenia (1-10 days, 1.8%; >40 days, 35.2%) and concomitant severe anaemia (0 days, 3.2%; >20 days, 31.0%). Multiple logistic regression revealed a strong correlation between IA incidence and hospitalisation under HEPA/LAF conditions (odds ratio [OR], 0.368 [95% confidence interval, 0.207-0.654]; p< .001) and duration of neutropenia (OR, 1.043 [1.023-1.062] per day; p< .001) and anaemia (OR, 1.044 [1.008-1.081] per day; p= .016). IA-associated fatal outcomes were non-significantly reduced under HEPA/LAF (OR, 0.077 [0.005-1.151]; p= .063). The protective effect of HEPA/LAF was not seen under posaconazole prophylaxis (OR, 0.856 [0.376-1.950]; p= .711). Implementation of HEPA/LAF was associated with a significant reduction in neutropenia-related IA in non-transplant haematological patients.

High-performance self-powered color filter-free blue photodetector based on wide-bandgap halide perovskites

Blue photodetectors (PDs) are attracting great attention for various applications. Commercial blue PDs based on inorganic GaP or InGaN absorbers are limited by their expensive, complex, and high-temperature fabrication techniques. Organic absorber-based blue PDs still have much lower photodetecting properties than inorganic blue PDs. In this study, a high-performance self-powered blue PD is developed using methylammonium lead halide (MAPbX3; X = I, Br, and Cl) perovskites based on the economic and facile solution process at low temperatures. Optimal composition is obtained through halide-composition engineering. Our best-performing device exhibits an average external quantum efficiency and an average detectivity of 42.7% and 8.65 × 1011 Jones, respectively, within the blue region. The peak responsivity of the proposed PD is 0.174 A W−1 at 455 nm, which is comparable to that of commercial gallium phosphide blue PD (0.180 A W−1 at 470 nm). Moreover, the proposed device exhibits excellent environmental stability under ambient air conditions. These findings will act as a basis for next-generation image sensor technologies, such as vertically stacked red/green/blue PDs.

Validating the reversible redox of alkali-ion disulfonyl-methanide as organic positive electrode materials

Alkali-ion reservoir organic positive electrode materials with high redox potential emerge as promising candidates for rocking-chair batteries. Despite recent major advances on coordinated Li-enolates and conjugated Li-sulfonamides, alike chemistries remain rare with clearly enormous room to explore and investigate. Herein, we report a new high-voltage redox functionality for alkali-ion storage based on aromatic di-sulfonyl methanide. The versatile paradigm chemistry of di-alkali p-phenylene-bis-diethylsulfonyl methanide (denoted as A2-p-TESO2, where A = Li+, Na+, K+) displays high voltage (3.13 vs Li+/Li), a two-electron reversible redox in both liquid phase and solid phase electrochemistry. A2-p-TESO2 also shows great stability under ambient air conditions in their alkali-ion reservoir states. This work not only suggests a new charge storage mechanism for organic batteries but also highlights the versatility of organic chemistry in designing new redox functionalities for next-generation organic rechargeable batteries.

Advanced Method of Variable Refrigerant Flow (VRF) Systems Designing to Forecast On-Site Operation—Part 1: General Approaches and Criteria

All the energetic management and controlling strategies in ambient air conditioning systems (ACS) are aimed to match design load to current needs. This might be achieved by determining a rational value of design thermal load without overestimation that can minimize its deviation from the actual values. The application of variable refrigerant flow (VRF) systems with speed-regulated compressors (SRC) is considered as the most advanced trend in building air conditioning due to the ability of SRCs to cover changeable heat loads without lowering their efficiency. The level of load regulation by SRC is evaluated as the ratio of the load range, regulated by SCR, to the overall design load range. With this, the range of actual changeable loads is usually supposed to be covered by SRC entirely while keeping the rest, unregulated, and load range unchangeable. However, to confirm this, the rest load range behind the regulated one should be investigated to estimate the efficiency of SRC operation. Therefore, the approach to dividing the overall thermal load range of ambient air conditioning into the ranges of changeable and unchangeable loads to compare with those covered by SRC is used. From this approach, the method of rational designing and shearing a design refrigeration capacity in response to current loading, based on the principle of two-stage ambient air conditioning, has been widened on the VRF systems to estimate the efficiency of SCR application. This was realized by imposing the load ranges regulated by SRC onto the ranges of changeable and unchangeable loads within the overall range of actual loading. The proposed innovative criteria and indicators for rational shearing the load ranges to match current duties and load level evaluation can reveal the reserves for improving the efficiency of SRC compressor operation and the ACS of VRF type as a whole.

Effects of Ambient Temperature and Humidity on Natural Deposition Characteristics of Airborne Biomass Particles.

In the production process of biomass energy with crop straw as the raw material, the indoor dust environment created by smashed plant fiber can affect the health of workers and lead to the risk of fire and explosions. The physical properties of biomass vary with the ambient air conditions, resulting in different deposition processes for airborne biomass particles. In this study, the deposition of biomass particles in different environments in an experimental chamber was examined by independently controlling the internal temperature and relative humidity. The results show that in the ambient temperature range of 20~40 °C and at a relative humidity of 25~65%, the water absorption rates of the biomass particles were 15.4~24.7%. The deposition rates of the airborne biomass particles with different sizes were 0.9~2.9 h-1, which positively correlated with the particle sizes in the same ambient conditions. The increase in ambient temperature and relative humidity promoted the deposition of biomass particles with diameters over 0.5 μm. For the particles with diameters below 0.5 μm, the deposition rates were nonlinearly related to the ambient temperature and relative humidity and were greater at lower temperatures. The significance levels of the factors influencing the particle deposition were particle size > ambient temperature > ambient relative humidity. For the biomass particles below 0.5 μm, the influence of the relative humidity on the deposition was much weaker than that of the temperature.

Vanadium Ferrocyanides as a Highly Stable Cathode for Lithium-Ion Batteries.

Owing to their high redox potential and availability of numerous diffusion channels in metal-organic frameworks, Prussian blue analogs (PBAs) are attractive for metal ion storage applications. Recently, vanadium ferrocyanides (VFCN) have received a great deal of attention for application in sodium-ion batteries, as they demonstrate a stable capacity with high redox potential of ~3.3 V vs. Na/Na+. Nevertheless, there have been no reports on the application of VFCN in lithium-ion batteries (LIBs). In this work, a facile synthesis of VFCN was performed using a simple solvothermal method under ambient air conditions through the redox reaction of VCl3 with K3[Fe(CN)6]. VFCN exhibited a high redox potential of ~3.7 V vs. Li/Li+ and a reversible capacity of ~50 mAh g-1. The differential capacity plots revealed changes in the electrochemical properties of VFCN after 50 cycles, in which the low spin of Fe ions was partially converted to high spin. Ex situ X-ray diffraction measurements confirmed the unchanged VFCN structure during cycling. This demonstrated the high structural stability of VFCN. The low cost of precursors, simplicity of the process, high stability, and reversibility of VFCN suggest that it can be a candidate for large-scale production of cathode materials for LIBs.

Layered transition metal oxides prepared by plasma-enhanced sintering technique as environmentally stable cathode for potassium-ion batteries

Layered transition metal oxides are deemed the most promising cathode materials for potassium-ion batteries owing to their high energy density and scalable design. However, their inherent moisture sensitivity thwarts their potential commercial realization. Herein, we show the efficacy of plasma-enhanced sintering technique in enhancing the environmental stability of K0.6Ni0.2Co0.3Mn0.5O2 layered oxide. The attained K0.6Ni0.2Co0.3Mn0.5O2 microspheres manifest a potassium-deficient surface layer that significantly suppresses surface hygroscopicity. Consequently, K0.6Ni0.2Co0.3Mn0.5O2 can be kept and handled in ambient air condition, while yet achieve competitive potassium-ion storage performance compared with other reported layered cathode materials with similar composition and microstructures. Overall, this work accentuates plasma-enhanced sintering techniques as an effective strategy to circumvent the moisture sensitivity of potassium-containing layered metal oxides, leverageable to hygroscopic layered metal oxides for other energy storage systems.