Ultra-Lightweight, Bendable Batteries
Stanford scientists are doing the unbelievable. Who could have thought of ordinary papers as batteries and super capacitors? But Stanford scientists are harnessing nanotechnology to quickly create ultra-lightweight, bendable batteries and super capacitors utilizing everyday paper. They have prepared ink with of carbon nanotubes and silver nanowires. Silver nanowires are highly conductive storage device. They are coating the sheet of papers with ink of carbon nanotubes and silver nanowires.
Yi Cui is the assistant professor of materials science and engineering. Cui’s work is published in the paper “Highly Conductive Paper for Energy Storage Devices.” It is published online in the Proceedings of the National Academy of Sciences. He states, “Society really needs a low-cost, high-performance energy storage device, such as batteries and simple supercapacitors.”
What is the difference between battery and capacitor? Batteries and capacitors both store electric charge. But capacitors hold it for a shorter duration than batteries. But, capacitors have an advantage. They can store and discharge electricity much more rapidly than a battery.
Cui says about the nanomaterials, “These nanomaterials are special. They’re a one-dimensional structure with very small diameters.” The small diameter is quite crucial because it helps the nanomaterial ink to stick strongly to the fibrous paper. This makes the battery and supercapacitor very durable. The paper supercapacitor can bear the 40,000 charge-discharge cycles. It’s better than lithium batteries as far as an order of magnitude is concerned. Cui explains that the nanomaterials also make ideal conductors because they move electricity along much more efficiently than ordinary conductors.
Bing Hu is a post-doctoral fellow. He put the above theory to practice. He took a small square of ordinary paper and dipped it with an ink. This deposited the nanotubes on the surface of the paper. This paper can then be charged with energy and viola! You are holding this wonder called paper battery.
Cui had previously experimented with plastic. He created plastic batteries using nano material. But he concluded that paper is a better option than plastic. Because, a paper battery is more long-lasting than plastic as ink sticks to paper more strongly. You can test the durability of paper batter by crumpling it, folding it or soaking it in acid or base, it’s performance will not deteriorate.
We all can conclude that paper battery will be more flexible than plastic one. By using that flexibility we can manoeuvre the battery in many possible ways. Cui explains, “If I want to paint my wall with a conducting energy storage device. I can use a brush.” Cui’s invention can be quite beneficial for electric or hybrid cars, because they demand quick transfer of electricity. The paper supercapacitor also enjoys the distinction of high surface-to-volume ratio. It will be advantageous for hybrid cars.
Peidong Yang is the professor of chemistry at the University of California-Berkeley. He says, “This technology has potential to be commercialized within a short time. I don’t think it will be limited to just energy storage devices. This is potentially a very nice, low-cost, flexible electrode for any electrical device.”
Cui foresees the biggest use of his paper batteries in large-scale storage of electricity on the distribution grid. We all know that surplus electricity generated at night could be stored in these paper batteries and later on utilized during rush or peak hours. Energy of wind and solar farms can also be stored in these paper batteries.
Yang put forth his opinion, “The most important part of this paper is how a simple thing in daily life — paper — can be used as a substrate to make functional conductive electrodes by a simple process. It’s nanotechnology related to daily life, essentially.”