https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1131&context=usdoepub

A review of polymer electrolyte membrane fuel cells: Technology, applications,and needs on fundamental research

Although current high-energy-density lithium-ion batteries (LIBs) have taken over the commercial rechargeable battery market, increasing concerns about limited lithium resources, high cost, and insecurity of organic electrolyte scale-up limit their further development. Rechargeable aqueous zinc-ion batteries (ZIBs), an alternative battery chemistry, have paved the way not only for realizing environmentally benign and safe energy storage devices but also for reducing the manufacturing costs of next-generation batteries. This Review underscores recent advances in aqueous ZIBs; these include the design of a highly reversible Zn anode, optimization of the electrolyte, and a wide range of cathode materials and their energy storage mechanisms. We also present recent advanced techniques that aim at overcoming the current issues in aqueous ZIB systems. This Review on the future perspectives and research directions will provide a guide for future aqueous ZIB study.

Recent Advances in Aqueous Zinc-Ion Batteries

Power consumption is forecast by the International Technology Roadmap of Semiconductors (ITRS) to pose long-term technical challenges for the semiconductor industry. The purpose of this paper is threefold: (1) to provide an overview of strategies for powering MEMS via non-regenerative and regenerative power supplies; (2) to review the fundamentals of piezoelectric energy harvesting, along with recent advancements, and (3) to discuss future trends and applications for piezoelectric energy harvesting technology. The paper concludes with a discussion of research needs that are critical for the enhancement of piezoelectric energy harvesting devices.

/pdf/powering-mems-portable-devices-a-review-of-non-regenerative-30r5zxggdp.pdf

Powering MEMS portable devices—a review of non-regenerative and regenerative power supply systems with special emphasis on piezoelectric energy harvesting systems

With a worldwide trend towards the efficient use of renewable energies and the rapid expansion of the electric vehicle market, the importance of rechargeable battery technologies, particularly lithium-ion batteries, has steadily increased. In the past few years, a major breakthrough in electrolyte materials was achieved by simply increasing the salt concentration in suitable salt–solvent combinations, offering technical superiority in numerous figures of merit over alternative materials. This long-awaited, extremely simple yet effective strategy can overcome most of the remaining hurdles limiting the present lithium-ion batteries without sacrificing manufacturing efficiency, and hence its impact is now widely felt in the scientific community, with serious potential for industrial development. This Review aims to provide timely and objective information that will be valuable for designing better realistic batteries, including a multi-angle analysis of their advantages and disadvantages together with future perspectives. Emphasis is placed on the pathways to address the remaining technical and scientific issues rather than re-highlighting the many technical advantages. New electrolyte materials can offer breakthroughs in the development of next-generation batteries. Here Atsuo Yamada and colleagues review the progress made and the road ahead for salt-concentrated electrolytes, an emerging and promising electrolyte candidate.

Advances and issues in developing salt-concentrated battery electrolytes

The push towards miniaturized electronics calls for the development of miniaturized energy-storage components that can enable sustained, autonomous operation of electronic devices for applications such as wearable gadgets and wireless sensor networks. Microsupercapacitors have been targeted as a viable route for this purpose, because, though storing less energy than microbatteries, they can be charged and discharged much more rapidly and have an almost unlimited lifetime. In this Review, we discuss the progress and the prospects of integrated miniaturized supercapacitors. In particular, we discuss their power performances and emphasize the need of a three-dimensional design to boost their energy-storage capacity. This is obtainable, for example, through self-supported nanostructured electrodes. We also critically evaluate the performance metrics currently used in the literature to characterize microsupercapacitors and offer general guidelines to benchmark performances towards prospective applications.

Microsupercapacitors as miniaturized energy-storage components for on-chip electronics

A PEM micro fuel cell system is described which is based on self-breathing PEM micro fuel cells in the power range between 1 mW and 1 W. Hydrogen is supplied with on-demand hydrogen production with help of a galvanic cell, that produces hydrogen when Zn reacts with water. The system can be used as a battery replacement for low power applications and has the potential to improve the run time of autonomous systems. The efficiency has been investigated as function of fuel cell construction and tested for several load profiles.

https://hal.archives-ouvertes.fr/hal-00277674/document

Optimization of efficiency and energy density of passive micro fuel cells and galvanic hydrogen generators

The invention relates to a micro fuel cell system (1) that comprises a membrane electrode assembly (MEA) (2) that is covered at the cathode and at the anode side with respective current-discharging foils (3, 4). Said current-discharging foils are provided with at least one gas-permeable opening (5, 6) each. Diffusion channels are disposed on at least one of the current-discharging foils (3, 4) on the side facing the MEA (2) and the width of said channels ranges between 1 and 300 micrometers. These diffusion channels replace for example porous gas diffusion layers or gas diffusion layers made of a nonwoven material and thus safeguard alone the microdiffusion of gas on the MEA (2). The diffusion channels are linked with the gas-permeable openings (5, 6) for guiding the gas and webs of the diffusion channels are provided with an electroconductive surface (11, 12) for contacting the MEA.

Micro fuel cell system

The ceramics were machined with a computer controlled Nd:YAG slab-laser. The laser parameters as well as the process parameters were optimized to obtain kerfs with good quality and cuts without cracks. Two applications were investigated: ceramics and silicon as substrates for embedded MCM-Ds (Multi Chip Modules, Deposited) and water-cooled heat sinks for single chips, multichip modules or laser diodes. For the embedded MCMs, windows were machined into the substrate. Bare dice and standard passive components (like capacitors or resistors) were inserted into these windows and fixed in their position with an epoxy. AlN, Al/sub 2/O/sub 3/ and Si were tested as substrate materials. The critical parameter was the mechanical stability of the substrate because of the thermal stress introduced by the following thin film process. For the second application, several heat sinks were produced in AlN. Different methods to clean the cooling channels were investigated. Maximum heat dissipation of water-cooled test-devices was determined for various channel geometries.

Laser machining of ceramics and silicon for MCM-D applications

The invention relates to a system for supplying a consumer with electrical power, comprising at least one fuel supply unit (9), which releases a gaseous fuel when an electric current flows therethrough, and comprising at least one fuel cell unit (8), inside of which the released gaseous fuel can be reacted with an oxidizing agent while generating power. The fuel supply unit is preferably a hydrogen generation cell comprising a zinc anode and a hydrogen cathode in an alkaline electrolyte.

Fuel cell system with an electrochemical hydrogen generation cell

A cost-effective and reliable technology allowing extreme miniaturization of batteries into glass chips and electronic packages has been developed, employing a dispense-print process for battery electrodes and liquid electrolyte. Lithium-ion micro-batteries (active area 6 × 8 mm2, 0.15–0.3 mAh) with interdigitated electrodes were fabricated, tested and finally compared with the traditional battery architecture of stacked electrodes. Commercial graphite and lithium titanate anode as well as layered nickel cathode materials were used. All the processes for the micro-battery fabrication were established during this work; in particular the micro fluidic electrolyte filling process that allows simultaneous electrolyte supply to all cells on a planar substrate. Electrode mass reproducibility was sufficient for adequate electrode balancing. Current capability similar to the conventional face-to-face electrode configuration was achieved with interdigital electrodes that can be fabricated much easily on a substrate level. The cells were successfully cycled; several 100 cycles can be achieved. Additional results of life-time characteristics and electrochemical impedance spectroscopy are presented as well. These rechargeable micro-batteries can be used for future extremely miniaturized electronic products.

Robert Hahn

Papers

Optimization of efficiency and energy density of passive micro fuel cells and galvanic hydrogen generators

Micro fuel cell system

Laser machining of ceramics and silicon for MCM-D applications

Fuel cell system with an electrochemical hydrogen generation cell

Characteristics of Li-ion micro batteries fully batch fabricated by micro-fluidic MEMS packaging