By Owais AliReviewed by Frances BriggsUpdated on Sep 11 2025As the demand for cleaner, more efficient, and sustainable energy storage grows, two technologies—supercapacitors and batteries—stand out. This article explores their properties, applications, environmental impacts, and the current commercial landscape to better understand their roles in the future of energy storage.
Image Credit: WINDCOLORS/Shutterstock.com
Supercapacitors vs Batteries: An Introduction
To store energy, batteries use chemistry, or rather, chemical potential. They consist of two electrical terminals (an anode and a cathode) separated by an electrolyte. When coupled to an external circuit, electrons and ions flow through the battery and the circuit, providing electricity. It's the potential difference between the anode and cathode that enables current flow and facilitates power delivery to connected electronics.
Supercapacitors, however, rely on an electric field. They operate based on the electrical "double layer" phenomenon, where oppositely polarized ions accumulate at electrode surfaces, separated by Helmholtz layers, creating a molecular dielectric that stores charges electrostatically. When the charge is released (which happens almost instantaneously) they are quickly delivered to power electronics.
Properties
Supercapacitors vs. Batteries: Calendar and Cycle Life
Recharging a battery involves forcing ions back into the anode to rebuild the electrochemical potential. This induces cyclic stresses that degrade electrode materials and the electrolyte components, reducing capacity and power density.
Some batteries, such as Li-ion (LIBs), form a solid-electrolyte interphase (SEI) layer that extends their life cycle by preventing electrolyte decomposition. However, SEI growth consumes electrode material over time, leading to aging and potential failure of the battery.
In contrast, supercapacitors can undergo almost unlimited charge/discharge cycles as they store energy electrostatically. There are minimal chemical or phase changes during operation since charge storage is non-Faradaic - based on physical electrostatic attraction rather than electron transfer reactions.
As a result, supercapacitors show no hard failure points and offer long-lasting performance. Even under heavy cycling, supercapacitors retain over 50 % of initial capacitance after one million cycles, vastly exceeding lithium-ion batteries.
Supercapacitors vs. Batteries: Operating Temperature
Batteries work optimally within a limited temperature range, usually -20 °C to 40 °C for lithium-ion. They experience reduced chemical-reaction activity and charge-transfer velocity at low temperatures, resulting in lower power and energy capabilities. In contrast, high temperatures can cause thermal runaway, resulting in uncontrolled overheating and potential explosion.
Supercapacitors, however, have a wider operating temperature range of -40 °C to +85 °C and do not undergo self-accelerating reactions, thereby eliminating concerns about thermal runaway.
Their electrostatic charge storage mechanism and lower internal resistance (compared to batteries) help minimize heat generated by impeding charge flow and prevent heat-generating chemical reactions.
Supercapacitors vs. Batteries: Energy Density
Batteries store energy as chemical energy, which is more energy-dense than electrostatic energy storage in supercapacitors. For example, LIBs reach up to 650 Wh/L, while high-end supercapacitors only achieve about 10 Wh/L, about 1.5 % of LIBs' energy density.
For this reason, batteries are preferred for applications requiring higher storage capacity, such as electric vehicles, grid, and renewable energy storage.
Supercapacitors vs. Batteries: Power Density and Charge Rate/Discharge Time
Power density directly relates to how quickly an energy storage technology can charge and discharge. Computer servers, manufacturing lines, and hospitals prioritize power density over energy density as they require immediate power delivery after a power loss.
Here, supercapacitors excel as they offer higher power density than batteries, with charge and discharge times in seconds or minutes, compared to hours for most batteries.
However, supercapacitors experience higher self-discharge, losing around 30 % of stored energy a month, while batteries lose only about 10 %.
Supercapacitors vs. Batteries: Efficiency
Supercapacitors are more efficient than batteries, especially under full load conditions, largely due to lower heat generation mechanisms that lead to power loss. They can achieve a round-trip efficiency of more than 98 %, while lithium-ion batteries' efficiencies are less than 90 %.
Image Credit: JLStock/Shutterstock.com
Applications
Supercapacitors vs. Batteries: Automotive, Transportation, and Mobility Applications
Commercial lithium-ion batteries are widely used to power electric vehicles due to their high energy density, but supercapacitors are increasingly finding applications in the automotive and transportation industries. Their high power density makes them well-suited for regenerative braking energy capture and storage, thereby improving efficiency in electric vehicles.
China has been using them in hybrid buses since 2006, reducing the reliance on lithium-ion batteries, making vehicles lighter and extending their range by up to 40 %. Toyota and Peugeot have also integrated supercapacitors to enhance the performance of their concept cars.
However, supercapacitors’ lower energy density still necessitates batteries to enable an adequate driving range. Therefore, engineers must balance tradeoffs between supercapacitors and batteries to optimize for acceleration, lifespan, range, and other factors.
Supercapacitors vs. Batteries: Renewable Energy
Storage batteries are essential for preserving electricity from intermittent power sources like wind and solar. They provide backup power for actuators in wind turbine systems and contribute to load balancing during peak demand.
Meanwhile, supercapacitors provide backup power for rapid blade pitch control in case of failures, act as dampeners for stabilizing voltage fluctuations in photovoltaic and wind energy systems, and support microgrid storage to address intermittency and fluctuating demand.
Supercapacitors vs. Batteries: Consumer Electronics and Tools
Batteries are powering most of our tools and electronics, but supercapacitors are making their presence felt in this market. For example, the BluCave FlashCell cordless screwdriver uses a supercapacitor instead of a battery, providing a quick 60-second charge time despite running for a shorter duration.
Sustainability and Environmental Impact
Batteries raise sustainability concerns because they rely on scarce and sometimes harmful materials such as lithium, cobalt, and nickel. Extracting and refining these resources can damage ecosystems and often involves ethical challenges tied to mining and refinery practices.
Disposal presents further risks. When end-of-life batteries break down in landfills, they can leak toxic chemicals into soil and water, threatening wildlife and human health.
Supercapacitors, on the other hand, are generally more sustainable. They often use more sustainable electrode materials such as activated carbon derived from renewable biomass. Their simpler composition also makes them easier to cycle compared to traditional batteries.
While advances in efficiency and recycling are helping to reduce the environmental footprint of batteries, supercapacitors currently have a clear edge in sustainability. Their reliance on abundant, non-toxic materials makes them easier to manufacture, reuse, and dispose of responsibly.
Commercial Landscape
The energy storage market is currently dominated by batteries, which benefit from established infrastructure, ongoing improvements, and massive investments. For instance, lithium-ion batteries power most electric vehicles, consumer electronics, and grid storage systems due to their proven performance and higher energy density.
On the other hand, supercapacitors are considered niche technology with specific applications due to their relatively lower energy density. However, ongoing research aims to improve the capacity of supercapacitors and reduce costs, potentially changing the landscape in the future.
Future Prospects
The future of energy storage is unlikely to rest on choosing between batteries and supercapacitors. Instead, scientists are looking to fuse the two. Hybrid systems promise the stamina of batteries with the sprinting power of supercapacitors—an arrangement that could offer the best of both worlds.
Is there a future in graphene batteries?
References and Further Reading
IEA. (2023). Global EV Outlook 2023-Trends in batteries. [Online]. Available at: https://www.iea.org/reports/global-ev-outlook-2023/trends-in-batteries
Joe Sleppy. (2023). Batteries vs. Supercapacitors? The Answer is Both. [Online]. Capacitech Energy, Inc. Available at: https://www.capacitechenergy.com/blog/batteries-vs-supercapacitors-the-answer-is-both
Mrozik, W., et al. (2021). Environmental impacts, pollution sources and pathways of spent lithium-ion batteries. Energy & Environmental Science, 14(12), pp.6099-6121. doi.org/10.1039/D1EE00691F
Sahin, M. E., et al. (2022). A comprehensive review on supercapacitor applications and developments. Energies, 15(3), p.674. doi.org/10.3390/en15030674
BBC. (2023). Why are batteries crucial for renewable energy? [Online]. Available at: https://www.bbc.com/storyworks/future/ngk-innovators-of-tomorrow/why-are-batteries-crucial-for-renewable-energy
Eaton. (2022). The major differences between supercapacitors and batteries. [Online]. Available at: https://www.eaton.com/content/dam/eaton/products/electronic-components/resources/brochure/eaton-supercapacitor-vs-batteries-white-paper-elx1150-en.pdf
Grigalunas, R. (2017) China takes the lead in adopting the all-electric bus equipped with supercapacitors. [Online]. Available at: https://www.escomponents.com/blog/2017/10/11/china-takes-the-lead-in-adopting-the-all-electric-bus-equipped-with-supercapacitors
Disclaimer: The views expressed here are those of the author expressed in their private capacity and do not necessarily represent the views of AZoM.com Limited T/A AZoNetwork the owner and operator of this website. This disclaimer forms part of the Terms and conditions of use of this website.