Bench Talk

(Source: Love Employee - stock.adobe.com)

For many years, scientists and engineers have tried to devise ways of making energy storage systems more efficient. This has manifested in a several ways, including trying to increase the storage capacity of energy storage devices, reducing the size of the devices, developing energy storage devices that can rapidly charge, and even manufacturing hybrid devices that take the best properties of multiple devices into a single device—one example being hybrid battery-ultracapacitor modules.

The increased reliance on electronic devices in our daily lives fostered the need for greater efficiencies, smaller sizes, and faster charging rates. So, developers constantly strive to improve these devices and provide more power while maintaining or reducing the size. Many conventional manufacturing methods limit how small and efficient developers can make these with bulk materials, so many academic scientists¹ and industrial manufacturers are now turning to nanomaterials to solve these challenges. The impact of nanotechnology on these devices over the last few years has been so significant that we are now starting to see some commercial energy storage devices on the market that use nanomaterials, many of which are in consumer products.

Nanomaterials exhibit properties that make them ideal for a wide range of energy storage devices. Because nanomaterials can have very different properties from each other, developers have endless possibilities for improving energy storage devices.

One of the main benefits for energy storage devices is the high electrical conductivity and charge carrier mobility of some nanomaterials, which enable electrons to travel and be stored more effectively. The quantum effects seen at the nanoscale can also be enhanced in some nanomaterials. Some nanomaterials possess quantum wells—energy potential wells—in which electrons can tunnel between if the wells are close enough together. This means that in some nanomaterials, the electrons can pass through the material without being impeded by any of the chemical bonds that make up the device, which, in turn, means that they don’t lose energy.

Nanomaterials are also inherently small and/or thin, enabling them to construct the miniature devices consumers want without compromising the device's efficiency. Nanomaterials also have an extensive and active surface area compared to bulk materials used for storing charge and/or ions, depending on the storage device.

Some other nanomaterials are incredibly insulating and can withstand high heat—much higher than the heat given off by high-power electronic devices. In a world where electronic devices are continually producing more heat as each technology generation passes, these insulating nanomaterials not only help to protect the electrical properties of the device; they can often dissipate heat within the device, meaning that it is less likely that heat spots and localized damage will occur, lengthening the usable lifetime of the device.

Different nanomaterials have had an impact on the properties of energy storage devices, and it’s not uncommon to use more than one nanomaterial to improve multiple properties of the device and/or induce synergistic effects between the nanomaterials that contribute to a more efficient device. Often it is the case that developers can use more than one nanomaterial in conjunction with each other to provide enhanced benefits. One example is stacking electrically insulating (dielectric) nanomaterials on top of highly conductive nanomaterials to reduce energy loss to the surroundings, protect the electronic charge carriers, and, in some cases, help to manipulate the direction of an electron.

Nanomaterials are now being used in a number of energy storage systems. Of these, batteries are the most common, with commercial batteries now being produced that contain nanomaterials. Given that Li-ion batteries present the biggest market to manufacturers, this is where the most impact has been made, but they have also been used to produce commercial lithium-sulfur (Li-S) batteries. While the most use of nanomaterials within batteries has been in the electrode, they are also used in solid and gel forms as the electrolyte within some batteries.

Another key area where the small size of such batteries has become useful is in the ever-evolving area of flexible and wearable electronic devices. In addition to stand-alone devices, a number of e-textiles² are being developed that use energy storage power the device, and these devices are only possible due to the small size and efficiency of the nanomaterials used in them.

Aside from batteries, some nanomaterials are used to construct the next generation of supercapacitors, and some modules are being developed that are a hybrid of both batteries and supercapacitors to try and exploit the beneficial properties of both while simultaneously trying to remove the issues associated with both.

These energy storage systems are used in many different modern-day technologies, and nano-inspired energy storage devices have potential across small-scale (handheld) systems and larger energy storage systems, such as electric vehicles. In fact, nanomaterials have been touted as one of the most promising ways of improving the relatively poor charging and energy storage capabilities of many batteries currently used in electric vehicles.

While nanotechnology-inspired energy storage devices have capabilities in larger systems, they are currently more prevalent in portable and handheld devices. A prime example includes a smartphone used in the Internet of Nano Things (IoNT). The IoNT means smaller sensors are needed, and nanotechnology-based batteries offer a way of powering such devices, with typical application areas spanning from medical sensing to environmental monitoring.

Many nanomaterials have properties that are highly suited to improving the performance, size, and charging capabilities of many energy storage devices. As the demand for smaller yet more efficient devices continues to grow, nanomaterials are going to play an even bigger part in these devices than they do now. We’re already starting to see commercial systems hitting the market across a range of handheld consumer products. These markets are likely to grow as more end-user manufacturers adopt these technologies.

• 1. “Nanotechnology in Batteries (Nano Battery).” Accessed November 28, 2022. https://www.understandingnano.com/batteries.html.


• 2. Berger, Michael. “Nanotechnology E-Textiles For Bio-Monitoring And Wearable Electronics.” Accessed November 28, 2022. https://www.technicaltextile.net/articles/nanotechnology-e-textiles-for-bio-monitoring-and-wearable-electronics-3762.