This study presents a comprehensive statistical analysis of experimental parameters for 12 printed supercapacitors (SCs) using previously proposed equivalent circuit models (ECMs). Statistical distributions and descriptive statistics, including mean, P-value, and standard deviation (std), are reported indicating a normal distribution for various SC parameters. A statistical method is introduced to determine the maximum potential std in capacitance of multiple SCs within an energy storage module, ensuring voltage limits are not exceeded. A linear relationship is discovered between the applied voltage on the module comprising three SCs in series and the maximum potential std of capacitance, ensuring safe operation. Additionally, a statistical method predicts the energy window range of the SC module after operating an IC chip, enabling better decision-making and system management. Monte-Carlo (MC) simulations predict the long-term charge and discharge performance of individual SCs and the series-connected modules. Results indicate that as long as the parameters’ std remains below a defined threshold, charging behavior remains consistent. The MC simulations provide insight into voltage window ranges after 31 days of self-discharge, aiding in performance prediction and risk assessment. The statistical study approach empowers researchers in the field of printed SC energy storage, supporting performance evaluation, design validation, and evidence-based decision-making.
Special mechanical properties have widely been demonstrated with bulk nanocrystalline materials. An increasing effort has been made to transfer such improvements also into thermal sprayed ceramic coatings. This paper focuses on such efforts in alumina-based ceramic coatings. The optimization of process conditions and effect of different process parameters on the mechanical performance of high velocity oxy-fuel (HVOF) sprayed ceramic coatings is discussed.
Energy-efficient, reliable and scalable machine-to-machine (M2M) communications is the key technical enabler of Internet-of-Things (IoT) networks. Furthermore, as the number of populated devices is constantly increasing, self-sustaining or energy-autonomous IoT nodes are a promising prospect receiving increasing interest. In this paper, the feasibility and fundamental limits of energy harvesting based M2M communication systems are studied and presented. The derived theoretical bounds are effectively based on the Shannon theorem, combined with selected propagation loss models, assumed link nonidealities, as well as the given energy harvesting and storage capabilities. Fundamental limits and available operational time of the communicating nodes are derived and analyzed, together with extensive numerical results evaluated in different practical scenarios for low power sensor type communication applications.
Microfibrillated cellulose (MFC) was fabricated from cellulose pulp using in-house mechanical fibrillation equipment. Subsequently, freestanding MFC films were fabricated with in-house developed hot-plate drying technique. The MFC films were tested as substrate materials for printed electronics patterns. Conducting patterns were fabricated on the MFC films using screen printing and vacuum evaporation. Electrical conductivity of the fabricated patterns was measured using four-wire technique. It was shown that the MFC films are suitable substrate materials for printing of functional electronic ink patterns, and thermal annealing of the patterns.
In this work we report a flexible energy supply unit made by printing flexible disposable aqueous supercapacitor modules onto a light harvester. In order to demonstrate simpler and more scalable manufacturing processes, we printed the supercapacitors monolithically instead of laminating electrodes face-to-face and integrated the series connections into the fabrication process. The supercapacitor modules were printed onto the backside of the Organic Photovoltaic (OPV) modules to combine energy harvesting and storage module for harvesting light under normal indoor conditions, storing it in a supercapacitor module, and thus offering power for low power IoT devices.
