One of the most discussed points of attraction at this year’s Mobile World Congress was the demonstration of Motorola’s bendable phone concept. The phone could wrap around one’s wrist.
Although fully flexible phone screens have been around for quite some time now, Motorola’s concept phone – bendable – was a class apart.
Not only was it a full-sized flexible smartphone with a camera, but it had an onboard generative AI that could conjure up a color scheme to match the wearer’s outfit within 10 seconds.
While bendable phones are rising, today, we will discuss the scenario involving batteries. The question is, if screens can now bend, why not batteries?
In a recent development, researchers in ACS Energy Letters have reported a lithium-ion battery with entirely stretchable components, including an electrolyte layer that can expand by as much as 5000%.
The good thing about the battery is that its stretchability properties do not take a toll on the battery’s performance, as it can sustain its charge storage capacity after nearly 70 charge/discharge cycles.
In the segments below, we will look into the properties of this battery in greater detail.
Bendable and Stretchable Batteries To Empower Electronic Gadgets With the Same Properties
The current research has come as a breakthrough in this space. It is because, to date, the efforts to build bendable and stretchable batteries have attempted to use and leverage woven conductive fabric or rigid components folded into expandable shapes like it is done in the Japanese paper folding art of origami.
However, this technique has a problem as a truly malleable battery requires it to be elastic in each of its parts, including the electrodes that collect charge and the charge-balancing components in the middle electrolyte layer.
But none of the prototypes we have seen so far come with full-fledged elasticity. Instead, they have moderate elasticity and entail a complex assembly process, further paralyzed with limited energy storage capacity, especially when used for a longer time with repeated charging and discharging.
The problem with charging inefficiency arises from the weak connection between the electrolyte layer and electrodes. Also, the fluid electrolyte could prove unstable, causing it to move around with the battery changing shape.
The team looked into these problems and worked out solutions.
Innovative Solutions to Achieve Full Elasticity
The team thought of using the electrolyte in a polymer layer fused between two flexible electrode films to create a completely solid, stretchy battery.
For electrodes, the team devised a strategy of spreading a thin film of conductive paste containing silver nanowires, carbon black, and lithium-based cathode or anode materials onto a plate.
Next, they applied a layer of polydimethylsiloxane, a flexible material commonly used in contact lenses, to the top of the paste.
Finally, on top of everything, the researchers applied a lithium salt, a highly conductive liquid, and the ingredients to make a stretchy polymer.
When all of these, stacked in multiple layers, were activated by light, the components came together to form a solid, rubbery layer that could stretch up to 5000% of its original length while having no problem in transporting lithium ions.
The entire device was sealed with a protective coating, and the stack, as mentioned earlier, included an additional layer of electrode film.
The researchers compared their solution with existing solutions available in the market that aim to achieve the same purpose. The comparison results were as follows:
Comparison Between the New Solid, Stretchy Battery Design with Devices Powered by Traditional Liquid Electrolyte
- The new version offered a six-times higher average charge capacity with a fast charging rate.
- The new solution could maintain increased stability while operating during 67 charging and discharging cycles.
- The polymer electrolyte operated steadily over 1000 cycles, with capacity dropping by 1% in the first 30 cycles. In a liquid electrolyte solution, the drop was as high as 16%.
The researchers believe that while much remains to be achieved, the research and its results are a highly affirmative and promising step forward in creating wearable or implantable devices that flex and move with the body.
While research institutions always act as pioneering agents for any industry to evolve with time, not all innovations prove feasible for real-life applications. Innovations need to have an element of applicability, and they also need to be conducive to adoption in a scaled-up operational paradigm.
In 2019, another team of researchers from the Johns Hopkins Applied Physics Laboratory developed a flexible lithium-ion battery that could operate under extreme conditions such as cutting, submersion, and simulated ballistic impact. The researchers also ensured that the batteries were incombustible.
“Water-In-Salt” And “Water-In-Bisalt” Electrolytes For Flexible Incombustible Batteries
The researchers offered new insights through the discovery of a new class of “water-in-salt” and “water-in-bisalt” electrolytes—referred to as WiS and WiBS—that, when incorporated in a polymer matrix, could reduce water activity and elevate the battery’s energy capabilities and life cycle.
At the same time, the mechanism freed the battery setup from flammability, toxicity, and highly reactive solvents present in them. The result was in the form of a flexible battery that was safe and powerful.
According to Konstantinos Gerasopoulos of APL’s Research and Exploratory Development Department, who also led the research:
“Li-ion batteries are already a constant presence in our daily lives, from our phones to our cars, and continuing to improve their safety is paramount to further advancing energy storage technology.”
Explaining the significance of the research, he said:
“Our recent paper shows improved usability and performance of water-based flexible polymer Li-ion batteries that can be built and operated in open air.”
While the ongoing research offered many breakthroughs, some companies have also been consistent in manufacturing flexible batteries for electronic items.
#1. Samsung
More than four years back, a patent added to the World Intellectual Property Office (WIPO) database showed that Samsung had developed a foldable battery to power phones of the same nature. The patented battery was designed with layers that allowed one of its cells to connect to another via a flexible commissure. This flexible connection crossed the hinge portion of the device, eliminating the need for two separate solid batteries.
The patent, as per reports, pertained to manufacturing batteries that could fit into the company’s Galaxy Fold-series. The success of the battery solution meant that the company did not have to worry about manufacturing two separate conventional components. Instead, one cell could flow into the next through the device’s hinge owing to its connecting central strip.
The patent claimed the hinge to be composed of “base material,” “mixture layers,” and “insulating separators.” According to experts, the mechanism allowed the active charge-bearing layers in the cells to interact while they could power the phone through a unified protection circuit module (PCM) and connect to its main board.
The Samsung Galaxy Z Fold 6 is already in the market, implying that Samsung’s foldable battery technology has been successful. The phone comes with a huge 7.6-inch OLED display and can support continuous web surfing over 5G (in this case, T-Mobile), with the display set to 150 nits of screen brightness.
According to a review of the gadget, the device averaged 10 hours and 35 minutes across four tests, beating the run times of Google Pixel Fold (10:21) but falling behind the OnePlus Open (11:31).
While giving his opinion on the battery capability of the Fold series, the reviewer – summarily – had the following to say:
“In daily use, I found the Z Fold 6 to deliver fairly strong battery life. With mixed usage, the battery indicator typically drops to the 20% to 25% range by 8 p.m., which is when I reach for a charger anyway. But I would certainly wish for more staying power on those days where I’m traveling or just constantly using Slack.”
Altogether, Samsung’s venture into foldable, flexible, or bendable phone batteries could fairly be called a success, with chances of improvement as always.
Financially speaking, Samsung Electronics recently reported its financial results for the first quarter of 2024, showcasing significant growth across various segments. The company achieved a consolidated revenue of KRW 71.92 trillion ($52.08 billion), marking a 13% increase compared to the same period last year. The operating profit skyrocketed by 933% to KRW 6.61 trillion ($4.78 billion), driven primarily by robust sales in its memory chip and smartphone divisions. Its smartphone division posted impressive results, with the Galaxy S24 series contributing significantly to revenue and operating profit.
#2. Jenax
Another company that has been doing pioneering work in the space of battery bendability or stretchability is Jenax. One of its most innovative flagship products is J.Flex, Jenax’s innovative, flexible, solid-state, fast-charging, rechargeable lithium-ion battery.
The company claims that its product can fully bend and move with the device without sacrificing power. In terms of its application, the battery caters to a large field, including IT wearables, health and fitness wearables, fashion, and the military.
The J.Flex batteries can be bent or rolled to enhance the flexibility of next-generation devices. Even with constant dynamic bending, it can perform at the same efficiency and capacity as the non-bending baseline level.
J.Flex supports customization as a designer can now unhesitatingly think of creating new shapes and sizes – not available previously – without sacrificing performance. The battery is also in compliance with international standards to ensure safety for all applications.
Click here for a list of top battery stocks to invest in.
Bend it like a Battery: Future Trends in Battery Bendability.
The volume of research that is underway in this domain makes the space promising for growth. Companies are increasingly getting innovative with their electronic gadget designs. They are imagining new aesthetics, creating a demand for bendability, stretchability, and flexibility properties in batteries that would eventually power their gadgets.
While we have already looked into two such research studies that carry the baton forward, we will conclude today’s discussion by looking at another one that could be full of applications in the days to come. A University of Houston team of researchers designed and developed a prototype of a fully stretchable fabric-based lithium-ion battery.
The researchers used conductive silver fabric as a platform and current collector, which proved to be a breakthrough. While explaining what the research had achieved and what its significance was, Haleh Ardebili, Bill D. Cook Professor of Mechanical Engineering at UH, who was responsible for driving the research, said:
“It seemed a natural next step to create and integrate stretchable batteries with stretchable devices and clothing. Imagine folding, bending, or stretching your laptop or phone in your pocket or using interactive sensors embedded in our clothes that monitor our health.”
Not only does the research hold the potential to open up new frontiers in the use of batteries in our everyday lives, but it also corrected a fundamental drawback that existed until then: the problem of rigidity. Much like the Johns Hopkins 2019 research, the UH researchers transformed rigid, lithium-ion battery electrodes into solid polymer electrolyte wearable, fabric-based, flexible, and stretchable electrodes.
According to Ardebili:
“The battery electrode must allow movement of both electrons and ions.”
This demand could be efficiently met with the use of weaved silver fabric as it could mechanically deform or stretch and still provide “electrical conduction pathways necessary for the battery electrode to function well.”
While the battery technology was still in its early testing phase, the researchers could well imagine its applicability in smart space suits, consumer electronics embedded in garments that monitor people’s health, and devices that interact with humans at various levels. However, like all inventions, this one’s viability was also dependent on scaling up the manufacturability, managing the cost structure, and similar factors.
In the days to come, we will see more innovations in our smartphones. Another growing space is wearable tech targeted at health and fitness. Fashion and accessories will also incorporate electronic elements.
All these will result in increased demand for stretchable batteries. The researchers will see increasing adoption of their tech across industries. However, one must not forget the aspects of safety, longevity, and performance when manufacturing them.
Click here to learn how advanced nanophotonics will help us build better smartphones.
