Search

The rapid evolution of wearable devices, the Internet of Things, and flexible displays has underscored the need for thin, flexible batteries. Screen‐printing has emerged as a mature technique for manufacturing these batteries, particularly those using a zinc chemistry. This study presents a commercially viable polymer electrolyte using a low‐cost organic electrolyte solvent, ethylene glycol. This first‐of‐its‐kind electrolyte formulation overcomes challenges associated with either water‐based or ionic‐liquid‐based solvents. The simple fabrication process allows for printing under ambient conditions and eliminates additional processing steps. Rheological analysis confirms that the developed polymer electrolyte is suitable for screen‐printing. Using this polymer electrolyte, a secondary printed battery with a 4 mAh cm−2 areal capacity is achieved. The study also investigates the mechanical behavior of the printed battery and emphasizes the importance of understanding interfacial stresses and bonding for designing optimal multilayered flexible batteries. This research offers an integrated solution, combining practical printed battery fabrication with battery testing and mechanical characterization, promising advancements in printed batteries and electronics. [ABSTRACT FROM AUTHOR]

Recent advancements have significantly improved the flexibility of lithium‐ion batteries (LIBs). The battery electrode contains a reaction layer and a current collector layer. Flexible battery electrodes, in which these layers are integrated, are fabricated in a single process, simplifying the electrode fabrication process. However, to date, integrated electrodes have lower conductivity than conventional two‐layer electrodes, and the process that maintains conductivity has not been simplified. This study proposes a liquid metal electrode ink that simultaneously plays the role of the reaction and current collector layers with high conductivity and can be formed in a single process via printing. It employs a gallium‐based liquid metal as a liquid current collector, embedded with Li4Ti5O12 or Li2TiS3 as active materials. These liquid metal electrodes exhibit a high electronic conductivity of 104 S cm−1 and can be fabricated without requiring the lengthy postprocessing time associated with conventional inks. Moreover, the ink can be applied directly to various insulating and nonflat curved substrates, demonstrating its charge–discharge performance, even when bent to a 1 mm radius to maintain flexibility. Liquid metal‐based electrode inks simplify the LIB fabrication process, contributing to efficient production methods for electrodes in future LIBs. [ABSTRACT FROM AUTHOR]

Aimed by the increasing interest in the field of printed batteries, the study recently has demonstrated the possibility to successfully gravure print composites working as electrodes for Li‐ion batteries. Gravure is one of the most appealing printing technique for the mass production of functional layers due to its unique ability to couple high speed and high resolution. The ink formulation is challenging because of the low viscosity ink requirement which makes difficult to obtain the proper functionality of the layer, especially in case of composite materials like electrodes, and a mass loading suitable for practical applications. Changing a material of the composite implies the study of a new gravure ink in terms of formulation and preparation process. Ruling the ink preparation can strongly decrease the process time promoting the industrial use of the gravure printing. For this reason, the study proposes a methodology, mainly based on the capillary number, able to suggest the best receipt for each specific ink. Here, a study case is reported, using lithium manganese oxide (LMO) as active material for the gravure printed cathode manufacturing. Such work gives the possibility to show the proposed methodology for ruling the ink preparation. [ABSTRACT FROM AUTHOR]

Screen-printed copper electrodes have the potential to replace silver and lithium electrodes in printed batteries and sensors owing to the abundance of copper, its competitive electrical properties, and the low cost of raw materials. Herein, copper microparticle-glycerol-based inks were screen-printed onto paper to develop highly conductive electrodes. The conductivity and particle connectivity enhancement of screen-printed electrodes are the main research topics. These parameters translate to usability including increased sensitivity for sensor applications and reduced resistivity for battery electrode applications. CuO nanoparticles of 50 nm were deposited onto the electrodes at a concentration of 1 μl/cm2, which led to a 4-fold decrease in sheet resistivity from 200 to 50 Ω/m2. The increased connectivity and formation of new channels due to the addition of nanoparticles were visualised via field emission scanning electron microscopy. The CuO nanoparticles were developed via a hybrid approach incorporating wet chemistry for high yield and laser ablation for colloidal conductivity and Zeta potential enhancement which reached up to −45 mV. An optimal screen-printing viscosity of 62 mPa s was achieved through a precise 1.95:1 mass ratio of Cu microparticles to glycerol. Heat treatment at 100 °C after screen-printing enhanced particle connectivity by reducing glycerol content in the ink.

In light of the growing interest in printed batteries, we recently demonstrated the possibility of employing industrial gravure printing in battery manufacturing. Gravure is the most appealing printing technique for the low-cost production of functional layers, but it is rarely investigated since the necessity to use diluted inks makes it difficult to obtain proper functionality, especially in the case of composites, and an adequate mass loading of the printed layer. For this reason, the ink formulation represents one of the main challenges; ruling on it could strongly boost the use of such a technique in industrial manufacturing. It is known that a viable method for obtaining good gravure printing quality is based on the Capillary number approaching unity. Taking into account such methods for the choice of ink and the process parameters, here a study of the printing quality influence on the functionality and the performances of the gravure printed layer is proposed in the case of an LFP-based cathode for Li-ion batteries. Good printing quality is necessary to obtain proper layer functionality, but specific parameters have to be considered for achieving high performance. [ABSTRACT FROM AUTHOR]

We present the application of drop-on-demand (DoD) dispensing technology for printing of silicon-based anodes. We show that the DoD printing technique is highly suitable for printing of arbitrary-geometry, high-activity SiNi nanoparticle anodes for Li-ion batteries. These anodes are on par with traditionally prepared anodes in terms of electrochemical behavior and performance and can be easily used in printed or any other type of Li-ion cells. We found that improved adhesion is necessary because of the complex geometry of printed anodes. High adhesion was achieved with the use of two types of CNT coatings on the copper current collector, and etching of the copper itself without the use of an intermediate coating. Printed anodes are electrochemically stable and perform according to most criteria as well as previously presented cast anodes, exhibiting high capacity (500–1200 mAh/g anode, depending on the type of cell) and have a relatively long cycle life (up to 500 cycles). Our results highlight novel strategies for 3D electrode printing, for potential uses in specialized batteries, and are of particular importance for advanced research and development. Printed electrodes shown here can be directly implemented as described, or be used as reference for the development of new types of electrodes for energy storage devices. [ABSTRACT FROM AUTHOR]

Recently, printing techniques are increasingly investigated in the field of energy storage, especially for the fabrication of custom‐designed batteries. Thanks to its many advantages, the most industrially used gravure printing would offer an innovative boost to printed battery production, even if, to date, such a technique is still not well investigated. In this study, for the first time, gravure printing is successfully used to prepare high‐performance conversion/alloying anodes for lithium‐ion batteries. A multilayer approach allows obtainment of the desired mass loading (about 1.7 mg cm−2), reaching similar mass loadings to those obtained by commonly used lab‐scale tape‐casting methods, allowing for their comparison. High‐quality gravure‐printed layers are obtained showing a very high homogeneity, resulting in a high reproducibility of their electrochemical performance, very close to the theoretical value, and a long cycle life (up to 400 cycles). The good results are also due to the ink preparation method, using a ball‐milling mix of the powders for disaggregation and homogenization of the starting materials. This work demonstrates the possibility of using the highly scalable gravure printing not only in the industrial manufacturing of printed batteries, but also as a useful tool for the study of new materials. [ABSTRACT FROM AUTHOR]

Aimed at the growing interest in printed batteries, widely used industrial gravure printing was recently proven to be able to produce high-quality electrodes for lithium-ion batteries (LiBs), demonstrating its utility in the study of new functional materials. Here, for the first time, gravure printing was investigated for the mass production of well-known low-cost graphite-based anodes for LiBs. Graphite was also chosen as a case study to explore the influence of process parameters on the layer microstructure and the performance of the printed anodes. In particular, upon decreasing the size of the active material nanoparticles through ball-milling, an enhancement in anode performance was observed, which is related to an improvement in the material distribution in the printed layer, even in the case of increasing mass loading through a multilayer approach. A further improvement in performance, close to the theoretical capacity, was possible by changing the ink parameters, obtaining a denser microstructure of the printed anode. Such good results further demonstrate the possibility of using gravure printing for the mass production of electrodes for printed batteries and, in general, components in the field of energy.

Sensing smart labels are an essential component of the Internet of Things (IoT) to provide identification and data. However, the widespread use of these labels into functional devices requires easy integration and power supply. Herein, a smart label is presented with integrated humidity sensor and printed battery. The smart label is composed by detection, communication, control, and energy subsystems. It is based on a screen printed RLC circuit and a printed humidity sensor with electrical linear response. The printed battery based on lithium iron phosphate as an active cathode material is fabricated with six single cells connected in series, leading to ≈100 mAh g−1. The printed humidity sensor has a linear response with a sensitivity of 0.004/% relative humidity (RH). Thus, it demonstrates the development of fully printed smart labels, improving integration into a variety of applications. [ABSTRACT FROM AUTHOR]

Printed batteries have undergone increased investigation in recent years because of the growing daily use of small electronic devices. With this in mind, industrial gravure printing has emerged as a suitable production technology due to its high speed and quality, and its capability to produce any shape of image. The technique is one of the most appealing for the production of functional layers for many different purposes, but it has not been highly investigated. In this study, we propose a LiFePO4 (LFP)-based gravure printed cathode for lithium-ion rechargeable printed batteries and investigate the possibility of employing this printing technique in battery manufacture.

This study establishes an approach to 3D print Li-ion battery electrolytes with controlled porosity using a dry phase inversion method. This ink formulation utilizes poly(vinyldene fluoride) in a mixture of N-methyl-2-pyrrolidone (good solvent) and glycerol (weak nonsolvent) to generate porosity during a simple drying step. When a nanosized Al2O3 filler is included in the ink, uniform sub-micrometer pore formation is attained. In other words, no additional processing steps such as coagulation baths, stretching, or etching are required for full functionality of the electrolyte, which makes it a viable candidate to enable completely additively manufactured Li-ion batteries. Compared to commercial polyolefin separators, these electrolytes demonstrate comparable high rate electrochemical performance (e.g., 5 C), but possess better wetting characteristics and enhanced thermal stability. Additionally, this dry phase inversion method can be extended to printable composite electrodes, yielding enhanced flexibility and electrochemical performance over electrodes prepared with only good solvent. Finally, sequentially printing this electrolyte ink over a composite electrode via a direct write extrusion technique has been demonstrated while maintaining expected functionality in both layers. These ink formulations are an enabling step toward completely printed batteries and can allow direct integration of a flexible power source in restricted device areas or on nonplanar surfaces. [ABSTRACT FROM AUTHOR]

Abstract: Thin-film batteries based on zinc/manganese dioxide chemistry with gel ZnCl2 electrolyte were manufactured as single (1.5 V) and double (3.0 V) cells from electrodes printed on paper substrates covered with different polymeric insulating coatings. Their properties were evaluated by means of electrochemical impedance spectroscopy and chronopotentiometry. Best performing cells achieved capacities in the range of 3 mAh cm−2 during discharge with 100 μA current, corresponding approximately to C/100 discharge rate. The influence of the cell elements on the overvoltage was examined and suggestions for the optimization of their performance were postulated. In particular, it was observed that limitations in the delivered power were governed by the poor conductivity of the carbon current collector. An optimized cell was built and showed a 4-fold improvement in the power delivered at 1 mA. [Copyright &y& Elsevier]

Aimed at the growing interest in printed batteries, widely used industrial gravure printing was recently proven to be able to produce high-quality electrodes for lithium-ion batteries (LiBs), demonstrating its utility in the study of new functional materials. Here, for the first time, gravure printing was investigated for the mass production of well-known low-cost graphite-based anodes for LiBs. Graphite was also chosen as a case study to explore the influence of process parameters on the layer microstructure and the performance of the printed anodes. In particular, upon decreasing the size of the active material nanoparticles through ball-milling, an enhancement in anode performance was observed, which is related to an improvement in the material distribution in the printed layer, even in the case of increasing mass loading through a multilayer approach. A further improvement in performance, close to the theoretical capacity, was possible by changing the ink parameters, obtaining a denser microstructure of the printed anode. Such good results further demonstrate the possibility of using gravure printing for the mass production of electrodes for printed batteries and, in general, components in the field of energy.

Inkjet printing can be used to manufacture flexible organic radical battery (ORB) electrodes. A reactive printing approach based on the thermal crosslinking of amine bearing redoxactive radical polymers is developed. The printed electrodes are stable for over one hundred charging/discharging cycles. [ABSTRACT FROM AUTHOR]

A battery design and fabrication process is demonstrated to make Lithium-ion (Li-ion) microbatteries with high capacity to power IoT devices. The battery consists of printed anode and cathode layers based on graphite and lithium cobalt oxide (LCO) respectively. The active area of the electrodes is scaled down to 1 mm2 and the resulting electrochemical performance is evaluated. These miniature batteries demonstrate a significantly higher discharge capacity (6.4 mAh/cm2) and energy density (23.6 mWh/cm2) than thin-film and thick-film, and 3D microbatteries. This work shows a miniaturized Li-ion battery capable of powering a MEMS-based wireless sensor system with peak current requirements as high as 4 mA, demonstrating its effectiveness as a power source for integrated electronics. [Display omitted] • A low-footprint, high-capacity Li-ion battery is designed and developed for MEMS-based sensors. • A facile fabrication process is developed by combining stencil printing and an adhesive based battery sealing method. • Li-ion micro batteries demonstrated a discharge capacity of ~6.4 mAh/cm2 and energy density of 23.6 mWh/cm2. • The application of Li-ion micro batteries as a power source for integrated electronics is demonstrated. [ABSTRACT FROM AUTHOR]

Solid‐state lithium‐ion (Li‐ion) batteries are a next generation energy storage technology that is able to address the transportation sector's need for increased safety and power density. Realizing this capability requires development of scalable manufacturing methods for solid electrolyte materials and for integration of such materials into battery cells. Herein, the first demonstration of aerosol jet printing is provided, which is a manufacturing‐ready 3D printing technique for fabrication of Li‐ion conducting solid polymer composite electrolytes. Deposition is performed directly on LiFePO4 cathode substrates. Aerosol jet printed electrolytes composed of polyethylene oxide (PEO), lithium difluoro(oxalato)borate (LiDFOB), and alumina nanoparticles are smooth, conformal, and nonporous, whereas those composed of PEO, lithium trifluoromethanesulfonate (LiTriflate), and alumina nanoparticles are conformal and porous. Conductivity of the printed solid polymer electrolytes tracks salt anion identity and concentration. The most conductive printed electrolyte, PEO/LiDFOB/alumina (EO:Li = 10:1), achieves conductivity >1 × 10−5 S cm−1 at 45 °C. In half cell configuration, batteries with this printed electrolyte can be discharged at C/15 with capacity >85 mAh g−1 at 45 °C and >160 mAh g−1 at 75 °C. The achievement of aerosol jet printed solid polymer composite electrolytes opens a path for scalable manufacturing of solid‐state Li‐ion batteries. [ABSTRACT FROM AUTHOR]

Lithium‐ion batteries (LIBs) are widely used in consumer electronics due to their rechargeability and high energy density. Commercial LIBs are fabricated in fixed geometries such as cylinder, coin, and pouch. However, for specialized applications such as wearable electronics and on‐device power systems, customizable LIBs with arbitrary geometry on three‐dimensional (3D) structures need to be developed. For this purpose, aerosol printing is uniquely suitable due to its flexible working distance, allowing deposition on nonplanar substrates with multiscale surface topologies. Aerosol printing of LiFePO4 cathodes and Li4Ti5O12 anodes for LIBs is presented. Electrodes with an arbitrary geometry, tailorable thickness and on nonplanar substrates can be realized. The highest areal capacity achieved is ≈7.1 mAh cm−2, which is at least twice that of conventional electrodes. Furthermore, to package the printed electrodes, 3D enclosures are fabricated via fused deposition modeling of polyvinylidene fluoride. The printed electrodes packaged in 3D enclosures exhibit 78.4% capacity retention after 30 cycles. With the two additive manufacturing processes, customizable LIBs on targeted objects can be realized. A nonplanar LIB conformably covering the edge of a block with specific capacity of 135 mAh g−1 is demonstrated. [ABSTRACT FROM AUTHOR]

Solid‐state lithium‐ion batteries promise to deliver the next generation of energy storage with necessary improvements in safety, energy density, and durability. However, their broad commercial success requires the development of scalable manufacturing processes to address fabrication challenges associated with composite electrodes, electrode/solid electrolyte interfaces, and thin solid electrolyte layers. In parallel with the need for innovation in solid‐state battery fabrication, there is a rapid progress in the field of 3D printing of functional materials. Hence, there is now the opportunity to consider how additive manufacturing informs fabrication processes for solid‐state lithium‐ion batteries. Herein, the fabrication requirements of solid‐state lithium‐ion batteries are described and recent examples of digitally fabricated solid‐state lithium‐ion batteries, components, and materials are highlighted. A critical review of initial efforts toward 3D printing of solid‐state lithium‐ion batteries provides the prospective to identify future challenges and prospects. [ABSTRACT FROM AUTHOR]

Inkjet and screen printing technologies are well known in the graphic arts industry for the reproduction of texts, images, and graphics. During the last decades, these printing technologies have been attracting increasing interest for the deposition of functional materials, e.g., in the field of printed electronics and for biological applications. However, their usage is mainly limited to 2D applications, i.e., rather flat deposits ranging from nanometers to several tens of micrometers in thickness. For 3D applications, sophisticated additive manufacturing technologies are developed to manufacture structures with high shape complexities. Herein, the potential of standard inkjet and screen printing technology as tools for the development of functional 3D objects is demonstrated. 3D functional structures printed by inkjet and screen printing technology combining conductive and nonconductive materials to a multi‐material structure are shown. A metal nanoparticle ink formulation is applied to inkjet‐print conductive metal pillars with a high aspect ratio (in the range of 50) used as vertical interconnects. The interconnects are encapsulated with an inkjet‐printed polymeric ink formulation and finally used as conductive tracks to light up a solid‐state light‐emitting diode (LED). Screen printing is applied to print primary batteries used as the power source for the LED. [ABSTRACT FROM AUTHOR]

Printed batteries have undergone increased investigation in recent years because of the growing daily use of small electronic devices. With this in mind, industrial gravure printing has emerged as a suitable production technology due to its high speed and quality, and its capability to produce any shape of image. The technique is one of the most appealing for the production of functional layers for many different purposes, but it has not been highly investigated. In this study, we propose a LiFePO4 (LFP)-based gravure printed cathode for lithium-ion rechargeable printed batteries and investigate the possibility of employing this printing technique in battery manufacture. [ABSTRACT FROM AUTHOR]

Printed batteries are an emerging solution for integrated energy storage using low‐cost, high accuracy fabrication techniques. While several printed batteries have been previously shown, few have designed a battery that can be incorporated into an integrated device. Specifically, a fully printed battery with a small active electrode area (<1 cm2) achieving high areal capacities (>10 mAh cm−2) at high current densities (1–10 mA cm−2) has not been demonstrated, which represents the minimum form‐factor and performance requirements for many low‐power device applications. This work addresses these challenges by investigating the scaling limits of a fully printed Zn–Ag2O battery and determining the electrochemical limitations for a mm2‐scale battery. Processed entirely in air, Zn–Ag2O batteries are well suited for integration in typical semiconductor packaging flows compared to lithium‐based chemistries. Printed cells with electrodes as small as 1 mm2 maintain steady operating voltages above (>1.4 V) at high current densities (1–12 mA cm−2) and achieve the highest reported areal capacity for a fully printed battery at 11 mAh cm−2. The findings represent the first demonstration of a small, packaged, fully printed Zn–Ag2O battery with high areal capacities at high current densities, a crucial step toward realizing chip‐scale energy storage for integrated electronic systems. Scaling limits for a fully printed Zn–Ag2O battery are explored to develop on‐chip energy storage for integrated electronics. With 1 mm2 electrodes, the printed Zn–Ag2O batteries demonstrate high areal capacities (11 mAh cm–2) at device‐relevant current densities. These batteries have thin form‐factors and utilize low processing temperatures, making them compatible with low‐cost, flexible substrates and emerging silicon integration strategies. [ABSTRACT FROM AUTHOR]

A novel photopolymerized poly(acrylic acid) separator is demonstrated in a printed, high-energy-density silver oxide battery. The printed battery demonstrates a high capacity of 5.4 mA h cm(-2) at a discharge current density of 2.75 mA cm(-2) (C/2 rate) while delivering good mechanical flexibility and robustness., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)