Batteries are among the most popular energy storage devices. These electrochemical devices can be charged and discharged many times without damage. They offer numerous benefits, such as reduced energy costs, increased energy independence, improved grid stability, and support for renewable energy integration.
But there is another electrochemical energy storage device that boasts far greater capabilities than batteries. That device is a supercapacitor, also called an ultracapacitor or electrochemical capacitor.
A high-capacity energy storage device, a supercapacitor, bridges the gap between batteries and conventional capacitors.
This device displays high power density, which is about a thousand times higher than that of rechargeable batteries. It also stores more charge than a capacitor and charges and discharges quicker than batteries.
Besides having long cyclic stability, supercapacitors have rapid charging/discharging efficiency, which makes them suitable for applications that need quick bursts of power. Today, supercapacitors are increasingly being used in a range of applications including lasers, portable power supplies, camera flash equipment, pulsed light generators, renewable energy systems, hybrid electric vehicles, and industrial power backup.
Now, a supercapacitor is made up of two electrodes, electronic conductors connected to the outer circuit, that are separated by electrolyte, an ionic conductor, and a separator, which is a membrane that electrically separates them so that the electrodes do not short circuit while allowing certain ions to pass through it to prevent an open circuit to the system.
Due to its high power density and environmental friendliness, such as recyclability, the supercapacitor is one of the most widely and actively researched energy storage systems.
In a supercapacitor, surface-controlled reaction mainly determines its capacitance. As such, a stable interface between electrode and electrolyte is key to achieving high performance and ensuring stable electrochemical performance.
Interfacial properties are crucial to ensuring high electrochemical performance, so researchers have been developing different methods to improve and overcome the issues associated with them.
However, all these attempts face considerable limitations such as scalability, cost, eco-friendliness, and several steps involved in processing. So, it is vital to come up with a sustainable solution that meets these criteria and can still achieve the high energy/power density supercapacitor for a long-term operation.
So, a team of researchers from three different institutions came together to introduce a new electrolyte additive, which consists of a conjugated biopolymer of gum kondagogu or sodium alginate (KS). This tree gum is not only widely available but also recyclable.
The introduction of the tree gum created a protective layer on the electrode’s surface, which prevented the formation of byproducts while allowing the facile ionic/electron transport. Notably, employing this novel additive concept in the supercapacitor system leads to enhanced electrochemical reliability.
At an even small KS concentration, i.e., 5 mg ml-1, the retention of capacitance improved as much as 35% to a whopping 93% for 30,000 cycles at a current density of 4.0 mA cm-2. This is simply “remarkable” given the use of acidic H2SO4 electrolyte and carbon-based electrode.
The study calls this the “earliest report” on a considerable improvement in the supercapacitor’s long-term operation by introducing a biopolymer conjugate electrolyte additive. This solution, thanks to its simplicity, low cost, and environmental friendliness, has the potential to be commercialized.
Tree Gum’s Role in Next-Gen Supercapacitors
Researchers from Universities in Scotland, South Korea, and1 India conducted the research, which was published this month in Energy Storage Materials.
This includes the University of Glasgow, Chung-Ang University, Ajou University, Amrita University, and Myongji University, which together designed the conjugated KS composite structure for a highly stable supercapacitor that offers biocompatibility and excellent electrochemical reliability.
The waste gum being utilized here is produced by trees in India. Tree gums have vast use cases across industries such as food, cosmetics, and pharmaceuticals. This particular gum, however, doesn’t have many practical uses.
In fact, the gums used are “a bit of a headache for the Indian government to dispose of,” noted the study’s corresponding author, Dr. Jun Young Cheong of the University of Glasgow’s James Watt School of Engineering. He added:
“With this research, we’ve found a way of making something genuinely impactful from this gum, creating a biodegradable, recyclable biopolymer which enables remarkable performance and could extend the useful life of supercapacitors dramatically.”
The use of acidic electrolytes affects supercapacitors’ long-term performance. By causing undesirable side reactions with their metal electrodes, they reduce their ability to hold a full charge over time.
Then there’s the problem of replacing, recycling, and disposing of supercapacitors at the end of their life. This contributes to the fast-growing problem of electronic waste, which poses significant environmental and health hazards.
So, the team used the gum kondagogu, a polysaccharide (complex biomolecule) produced by the bark of the Cochlospermum Gossypium or Kondagogu gum (KO) tree. Researchers combined it with sodium alginate to produce a sponge-like biopolymer named ‘KS’.
Adding this biopolymer to the acidic electrolyte formed a guarding layer on its carbon electrodes, which helped prevent the electrodes’ physical degradation. This protection was provided without affecting the process of ion transport, which enables the supercapacitor to charge and discharge.
The improved electrolyte significantly enhanced the performance of the supercapacitor.
“In the lab, we’ve shown excellent performance over 30,000 cycles. If we were to run one cycle per day, the supercapacitor could theoretically last more than 80 years without losing significant performance, which could mean that supercapacitors could be used in devices for much longer without being replaced.”
– Dr. Cheong
The research is actually based on Dr. Cheong’s ongoing research into using bio-waste in batteries. His research has also shown the effectiveness of using gum binders, which are soluble in water, in graphite anodes in Li-ion batteries.
The “water-soluble biowaste gum binders for natural graphite anode for lithium-ion batteries” research was published2 last summer, which talked about replacing the conventional polyvinylidene fluoride (PVdF), that employs environmentally harmful N-Methyl-2-pyrrolidone, with a water-soluble binder.
The study detailed the fabrication of natural graphite-based anodes using PVdF and water-soluble biowaste (W-SB) binders from the Cochlospermum gossypium tree’s gum. Both of these used 10 wt% of binder.
The NG-W-SB electrode exhibited good mechanical properties and maintained structural integrity after cycling, promoting low charge transfer resistance on the electrode. It also showed high current peaks in the first cycle, indicating enhanced electrochemical performance, unlike slightly low peaks of the NG-PVdF electrode, which further experienced capacity degradation just after 200 cycles. NG-W-SB, meanwhile, has a higher stable capacity retention that goes up to 360 cycles.
“Generally, W-SB binders showed highly enhanced cycling retention characteristics, comparable rate capabilities, and lower electrode resistance, which opened a new avenue for adopting biowaste (gum) as a functional water-soluble binder for LIBs applications,” noted the study.
Another of Dr. Cheong’s research3 includes, “Organic material-derived activated carbon for eco-friendly mulberry paper supercapacitor,” where activated carbon (AC) was prepared using orange peel (OP), a common waste, which was then coated on mulberry paper (MP), which demonstrates hydrophilicity, high holocellulose content, and strong bonding with active material. Another coating of poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) was used to fabricate a dual-coated MP for the supercapacitor here.
Other Developments in the Supercapacitors Space
Given how critical supercapacitors are in various applications, researchers around the world are actively investigating ways to improve their performance.
Plasma Treatment to Improve the Capacitance
Just earlier this month, scientists at the Skolkovo Institute of Science and Technology (Skoltech) of Russia unveiled a plasma treatment that can double the capacity of supercapacitors.
The team, according to the study’s principal investigator, Assistant Professor Stanislav Evlashin, is looking into ways to improve supercapacitors’ performance “by tinkering with the carbon-based material used in their electrodes.”
There are two ways to increase the amount of energy a supercapacitor stores, explained Evlashin:
“Either you enhance the effective surface area of the electrodes by intricate surface design or you introduce foreign atoms into the carbon material of the electrodes.”
Their study focused on the effect of introducing foreign atoms into the carbon material of supercapacitor electrodes via plasma treatment.
The team tested the impact of plasma with six different chemical compositions on the capacitance of carbon nanowalls, but only the plasma composed of a nitrogen and argon mixture demonstrated substantial improvement.
“We found that what happens first is that the amorphous carbon remaining after the growth of carbon nanowall structures is cleared away. This is followed by the formation of new defects and the incorporation of heteroatoms into the carbon material structure. Amorphous carbon, along with the heteroatoms of nitrogen, contributes to the occurrence of pseudocapacitance.”
– Evlashin
Advancing Performance Through Electrode & Material Engineering
This week, researchers from the University of California engineered electro-crystallization orientation4 as well as surface activation under wide-temperature ZHSCs or zinc ion supercapacitors.
As the study noted, matching the anode and cathode’s capacity is necessary to maximize electrochemical cell performance. Therefore, they presented two approaches to leveling the utilization of electrodes in ZHSCs.
This includes minimizing dendrite formation, which increases the cycle life, by modifying the anode current collector with copper nanoparticles. The other strategy was increasing the capacity of the activated carbon cathode through an electrolyte reaction.
The full cell maintained 84% of its capacity even after 50,000 full charge-discharge cycles up to 2 V. Its cumulative capacity, meanwhile, was 19.8 Ah cm−2, which exceeds ZHSCs, making this device design “promising for high-endurance applications, including uninterruptible power supplies and energy-harvesting systems that demand frequent cycling,” it stated.
A study from last month, meanwhile, recommended5 modifying the anionic structure of lithium cobalt oxide to improve the energy density and charge storage capability of supercapacitors.
For this, lithium cobalt oxide was modified to LiCoO1.6(F0.8Cl0.2)0.4, which exhibited impressive performance characteristics, including capacitance of 512 F g−1 and a coulombic efficiency of just over 92% after 4000 cycles at a current density of 2 A g−1. The electrochemical stability of the modified material at elevated current rates, as well as low equivalent series resistance, as per the study, “positions it as a significant candidate for future advancements in supercapacitor technology.”
Plastic Supercapacitors for More Energy Storage
Researchers are even using plastic to improve supercapacitors. UCLA chemists developed textured, fur-like PEDOT nanofibers that have more surface area to store charge and superior electrical conductivity.
PEDOT or poly(3,4-ethylenedioxythiophene) is a transparent and flexible film that is applied to the surfaces of electronic components and photographic films to protect them from static electricity. Its potential for energy storage is rather limited as PEDOT materials do not have the electrical conductivity and surface area required to hold large amounts of energy.
However, using an innovative method, the chemists controlled PEDOT’s morphology to grow nanofibers precisely. The vapor-phase growth process created vertical PEDOT nanofibers that looked like dense grass growing upward.
“The material’s unique vertical growth allows us to create PEDOT electrodes that store far more energy than traditional PEDOT.”
– The corresponding author, UCLA materials scientist Maher El-Kady
The team then created a supercapacitor using PEDOT structures that stored almost ten times more charge than conventional PEDOT and lasted almost 100,000 charging cycles.
According to the corresponding author, Richard Kaner, who is a professor of chemistry, as well as materials science and engineering:
“The exceptional performance and durability of our electrodes show great potential for graphene PEDOT’s use in supercapacitors that can help our society meet our energy needs.”
Click here to learn all about self-charging supercapacitors.
Adding Supercapacitors to Batteries to Boost Charging Speed
Amidst all this research, even the German automaker BMW has filed for a supercapacitor patent that will charge hybrid race cars within a minute.
The company is exploring the potential of adding a motorsport-specific supercapacitor to batteries to significantly reduce the charging time. As per the application, coupling a hybrid supercar with a capacity of over 20kWh to an existing battery-based system will help overcome some of the key negatives of both systems.
BMW estimates that “for a customer who wants to drive the vehicle on the racetrack, this may offer the opportunity to drive continuously at the physical limits with short interruptions.”
Its competitor, Volkswagen Group, meanwhile, is already using a supercapacitor in the Lamborghini Sian. The supercapacitor stores electrical energy, which is then fed to an electric motor. The Sian has a 25kW motor built into the gearbox to provide an e-boost to the 577kW 6.5-litre V12 or power it entirely on electricity during low-speed maneuvering.
Innovative Companies in the Field
The size of the global supercapacitor market is in the billions of dollars, driven by the rising demand for sustainable and energy-efficient energy storage solutions. Hence, many companies, such as Panasonic Corporation and Skeleton Technologies, are working on improving the technology.
A prominent name in this space is AVX Corporation, which was acquired by Japanese electronics manufacturer Kyocera Corporation in 2020 upon which AVX common stock ceased trading on the NYSE. Kyocera’s stocks, meanwhile, are trading in the OTC market (KYOCF:OTCPK) at $10.70, which puts its market cap at $15.85 billion. It pays a dividend yield of 3.12%.
KEMET Corporation is also known for offering a wide range of supercapacitors with high-performance capabilities that can be used as secondary batteries when applied in a DC circuit. According to its official website, the devices are best suited for use in low-voltage, DC hold-up applications. Originally a US company that went public on the NYSE in 1990, KEMET was acquired by Taiwanese company Yageo Corporation in 2020.
Maxwell Technologies is yet another prominent manufacturer of ultracapacitors. Tesla acquired it in 2019, only to sell it to UCAP Power in 2021. Despite selling Maxwell, the $817.34 billion market cap EV and battery manufacturer retained its dry electrode manufacturing process, which is based on its capacitor technology. TSLA shares are currently down over 37% YTD as they trade at $248.80.
Then there’s Australia-based CAP-XX, which manufactures thin, prismatic supercapacitors for use in consumer handheld devices, commercial and industrial electronics, and clean energy applications. It is listed on the London Stock Exchange AIM market.
CAP-XX’s supercapacitors boast high energy density, high cell voltage, and extremely low leakage current. With the help of its supercapacitors, manufacturers can reduce battery size, weight, and cost, the number and cost of components involved, and their environmental impact.
Conclusion
While batteries have captured the limelight, supercapacitors are gaining traction as they become one of the most crucial components in the global energy ecosystem. After all, they can offer high efficiency, long cycle life, and instantaneous power delivery.
Currently, supercapacitors are complementary in the energy storage sector for applications like consumer electronics, renewable energy smoothing, hybrid EVs, and backup power, which require quick charge-discharge cycles and long operational lives.
So, the broader adoption of supercapacitors is still limited by cost, material, and environmental concerns. However, approaches like tree gum-based biopolymers are tackling these very challenges, which points to a promising future for supercapacitors. Still, commercialization will take time, but once it ramps up, supercapacitors can become mainstream and play a key part in sustainable energy systems.
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Studies Referenced:
1. Lee, S., Park, J. Y., Yoon, H., Park, J., Lee, J., Hwang, B., Padil, V. V. T., Cheong, J. Y., & Yun, T. G. (2025). Long-lasting supercapacitor with stable electrode-electrolyte interface enabled by a biopolymer conjugate electrolyte additive. Energy Storage Materials, 67, 104195. https://doi.org/10.1016/j.ensm.2025.104195
2. Chang, J. H., Pin, M. W., Msalilwa, L. R., Shin, S. H., Han, C., Yu, H., Chandio, Z. A., Padil, V. V. T., Kim, Y., & Cheong, J. Y. (2024). Water-soluble biowaste gum binders for natural graphite anode for lithium-ion batteries. Journal of Electroanalytical Chemistry, 967, 118467. https://doi.org/10.1016/j.jelechem.2024.118467
3. Han, Y., Yoon, H., Cheong, J. Y., & Hwang, B. (2025). Organic material-derived activated carbon for ecofriendly mulberry paper supercapacitor. International Journal of Energy Research, 2025, 8791702. https://doi.org/10.1155/er/8791702
4. Yao, L., Koripally, N., Shin, C., et al. (2025). Engineering electro-crystallization orientation and surface activation in wide-temperature zinc ion supercapacitors. Nature Communications, 16, 3597. https://doi.org/10.1038/s41467-025-58857-5
5. Hashemzadeh, S. M., Khorshidi, A., & Arvand, M. (2025). Anion engineering in lithium cobalt oxide for application in high-performance supercapacitors. Scientific Reports, 15, 10064. https://doi.org/10.1038/s41598-025-95338-7