Recently, researchers at Rensselaer Polytechnic Institute in the United States made the world's thinnest material, graphene, into a piece of paper, which was then shocked with the flash of a laser or a camera flash, causing it to make holes. The internal structure of the material is spaced apart to allow more electrolyte to "wet" and lithium ions in lithium-ion batteries achieve high-rate channel performance. This graphene anode material charges or discharges 10 times faster than the graphite anodes currently used in lithium-ion batteries and can drive electric vehicles in the future.
Rechargeable lithium-ion batteries are used as industry-specific products for a range of devices such as mobile phones, laptops and tablet computers, and electric vehicles. Lithium-ion batteries have a high energy density and can store large amounts of energy, but they cannot receive or release energy quickly when they encounter low power densities. To solve this problem, the nanomaterial specialist Nicky led the team to create a new type of battery that can not only accommodate a large amount of energy, but also quickly receive and release energy.
According to the researchers, the main hurdle for lithium-ion battery technology is the limited power density and the inability to quickly receive or release large amounts of energy. This type of graphene paper battery, which is structurally "defective," can help overcome these obstacles. Once commercialized, this achievement will have a significant impact on the development of new batteries and electrical systems in electric vehicles and portable electronic products. The battery can also greatly reduce the time required for charging portable electronic devices such as mobile phones and laptops and responders.
The solution for the new battery is to create a large piece of graphene oxide paper that is equivalent in thickness to a piece of everyday paper and that can be made into any size or shape. Then the graphene paper is exposed to laser light and the digital camera flash Flash under. The heat of the laser or flash penetrates the paper and causes a small explosion. The oxygen atoms in the graphene oxide are driven out of the structure. The graphene paper becomes devastated: numerous cracks, voids, voids, etc. The graphene paper is expanded by 5 times the thickness, thereby creating a large void in the single graphene sheet.
The researchers found that this damaged single-layer graphene paper can be used as an anode for lithium-ion batteries. Lithium ions use these cracks and pores as shortcuts, and they quickly move in and out of graphene, greatly increasing the overall power density of the battery. . They have experimentally demonstrated that the anode material charges or discharges 10 times faster than conventional anodes in lithium-ion batteries without causing a significant loss in its energy density, even after more than 1,000 charge/discharge cycles. . In addition, it is important that the high conductivity of the graphene sheet enables electrons to be efficiently transported at the anode.
The researchers said that these graphene paper anodes are easy to adjust, can be made to any size and shape, and exposing them to the flash of a laser or camera flash is a simple, inexpensive copying process. They will next pair high-power cathode materials with graphene anode materials to build a complete battery.
The results of this study were published in the recent issue of ACS Nano, the American Chemical Society.
May 01, 2023