Supercapacitors instead of batteries: device, feature comparison, benefits of use, reviews

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:42

The idea of a high specific capacitance was explored in the 1960s, but today there is a new wave of increased interest in this technology, due to the unique combination of performance properties of the final product. Today, on the basis of this technology, various modifications of supercapacitors and ultracapacitors are produced, which may well be considered as a full-fledged power battery. The supercapacitor concepts shown below show that their future competition with conventional battery packs (batteries) is not so fantastic.

What is a supercapacitor?

In essence, this is an optimized electrochemical battery, made in the form of a compact capacitor. Even with a cursory comparison of the device with a typicalbattery for a car, you can highlight the obvious difference in size, and in practice, the benefits will also come to the surface in the form of a longer service life and power. In other words, supercapacitors can be used instead of batteries, although with some reservations due to limitations in terms of energy potential accumulation. Such nuances still take place due to the imperfection of the technological development of ionistors, however, the situation is changing under the pressure of the market with its growing requirements for batteries.

Design and product design

The basis of this capacitor is formed by two electrodes, between which the electrolytic medium is traditionally placed. Differences from the battery can be observed in the structure of materials for the manufacture of electrodes, the plates of which are coated with porous activated carbon. As for the electrolyte, organic and inorganic mixtures can be used in this capacity. Structurally, the technical solution of insulation in the structure of supercapacitors also stands out. Instead of battery aluminum plates with a dielectric layer, components with optimal properties of ionic and electronic conductivity are used. If we continue the concept of the possible use of a supercapacitor as a battery, then porous carbon could well act as an electronic conductor, and a solution of sulfuric acid could act as an ionic conductor. In this way, an optimal charge separation layer between the electrodes can be provided without the additional inclusion of bulky insulators.

Varieties of supercapacitor

Already today, there are several directions in the development of ionistors. The most noticeable and promising are the following types of devices:

• Double layer capacitors. The standard model, which uses the above-mentioned electrodes made of electrically conductive material, and a special separator is used as an electrolyte. The accumulation of energy potential occurs as a result of charge separation on the electrodes.
• Pseudocapacitors. A rechargeable battery made from this type of supercapacitor can be a very successful solution, since it offers more advanced ways to store energy. Firstly, the principle of the Faraday mechanism is involved, associated with the processes of energy accumulation in conventional batteries. And secondly, the basic scheme of electrostatic interaction between electrodes in a double electric layer is also preserved.
• Hybrid capacitors. An intermediate concept that combines the individual positive features of batteries and capacitors. Such devices typically use a combination of electrodes made from mixed oxides and doped polymers. Further development of this direction is associated with the use of composite materials supplemented with carbon carriers and conductive polymers.

Key Features

Today it is difficult to talk about the well-established performance of supercapacitors, becausetechnology is constantly being improved, and adjusted for the improvement of electrochemical current sources. But if we take the average data on the main characteristics of supercapacitors, then specific indicators will look like this:

• Charging time - 1 to 10 seconds
• The number of charging cycles is about 1 million, which corresponds to 30,000 hours.
• Voltage in the block cell - range from 2.3 to 2.75 V.
• Energy intensity - standard value 5 Wh/kg.
• Power - about 10,000 W/kg.
• Durability - up to 15 years.
• Operating Temperature -40°C to 65°C.

Comparison with conventional batteries

The main distinguishing parameters are the rate of accumulation of energy and the degree of return of the electric charge. Due to the use of a double layer of electric potential near the supercapacitor with similar dimensions, the area of the working surface of the electrodes increases. That is, we can talk about combining the best properties of the battery and the capacitor as such. If we compare the distribution of the currents of the battery and the supercapacitor to the load, then the uniformity of the volumes of the consumed current will be generally identical, but with two corrections. During the operation of the battery, it is possible to shift the largest current towards the element located in the lower part of the block, and in the case of ionistors, in principle, the potential will be less due to the low voltage. Also, significant differences include the difference in the working resource - supercapacitors serve approximately 25-30% longer in time, not to mentionhigher rate of doable duty cycles.

Advantages of operating supercapacitors

If we generally consider the positive effects of using supercapacitors instead of batteries, then the following qualities will come to the fore:

• The high energy density of supercapacitors allows them to be used in electronic devices as a short-term power source.
• Environmental safety. Of course, electrochemical components are still retained in the design, but their toxic effects are constantly decreasing.
• Possibility of using energy from renewable sources - wind, sun, water and land.
• Expansion of opportunities for structural integration of batteries - for example, for maintenance of complex power plants, hybrid electric machines, hydrogen-fueled vehicles, etc.

It is worth noting some of the advantages of a supercapacitor in relation to a conventional capacitor. There are few of them, but a large capacity for energy storage is fundamentally important. According to this indicator, not all modifications of ionistors can compete with batteries, however, in comparison with capacitors in the electric capacity parameter, they confidently win.

Positive reviews of supercapacitors

Testing and partial application of supercapacitors today take place in a variety of industries. As the reviews on the operation of these devices show, they confirm the manufacturers' statements about the highreliability, environmental safety and high capacity. What is especially important from the point of view of comparing supercapacitors and batteries, the former are not so demanding to create special conditions during physical handling. This is partly due to the same low toxicity of the components, but to a greater extent, the ergonomics of operation is due to the high degree of protection of the case. That is, the user does not need to provide special devices for maintenance of supercapacitors in sealed conditions. Also, the low weight and optimized dimensions make it easier to carry out routine maintenance operations.

Negative reviews of supercapacitors

There are also weaknesses in this kind of capacitors, which are also clearly manifested in practice. In particular, users point to their low energy density, low performance and not always sufficient voltage level, which makes it necessary to use several elements to serve one target consumer unit. In many ways, these shortcomings prevent the use of supercapacitors instead of batteries today, although, again, technological development is more likely to solve these problems.

Prospects for the development of capacitors

According to experts and developers of batteries, in the near future, new generation capacitors will be used everywhere. This will become possible due to the active increase in the specific capacity of devices. It's worth itadd and improve the technical and structural characteristics of supercapacitors, which primarily concerns dimensions and weight. At the same time, tests of ionistors with a power of up to 2.5 mW are already being organized today. In the future, such systems can be used in the maintenance of transport networks, industrial facilities and residential complexes.

Conclusion

The supercapacitor concept is considered to be the optimal solution in situations where there is a short-term need for power supply with live charge. In part, this is a contradiction with the idea of electrochemical batteries, which are focused on long-term maintenance of power with certain parameters. But is it possible to use a supercapacitor instead of a battery in a car, given this operational feature? With a high degree of probability, advanced auto concerns will use high-capacity capacitors, but only in special hybrid versions that combine the positive qualities of supercapacitors as such and traditional electrochemical components. For example, today such solutions are used in the form of a combination of an electrochemical lead-acid structure and a supercapacitor.