University of California, Santa Cruz: 3D printing graphene airgel supercapacitors can be made strong
Scientists have recently reported an unprecedented performance the result of a super capacitor electrode. Researchers selected airgel is a graphene material, and using a 3D printer technology, constructed of a porous three-dimensional scaffold with pseudocapacitive electrode material. In laboratory tests, the new area of the electrode to achieve the highest capacitance (per unit electrode surface area of each store charge) of the supercapacitor report ever. University of California Santa Cruz and Lawrence Livermore National Laboratory (LLNL) scientists recently reported unprecedented performance the result of a super capacitor electrode has. Researchers selected airgel is a graphene material, and using a 3D printer technology, constructed of a porous three-dimensional scaffold with pseudocapacitive electrode material. Chemistry and biochemistry professor at the University of California, Santa Cruz Yat Li said that in laboratory tests, this new type of electrode area to achieve the highest capacitance (storage unit electrode surface area per charge) ever reported by a super capacitor. Prepared on the outcome of this study and the electrode holder, and on October 18 in a way that papers published in the \”Joule\”. Said super capacitor as an energy storage device having the advantage of fast charge (seconds to minutes), and may remain after its storage capacity by tens of thousands of cycles of charging. And its application to regenerative braking system is a multi electric vehicles and other applications. Compared with batteries, they are not stored in the same space have fewer energy, and their charging time is not long. But with advances in ultracapacitor technology, which may have a wider range of applications, perhaps in some areas in competition with the battery. In earlier studies, UCSC and LLNL researchers demonstrated ultrafast super capacitor electrode prepared using 3D printing techniques such graphene airgel. In this new study, they are mainly used to improve a graphene airgel material for producing a porous scaffold, and then loaded on the carrier of the pseudo capacitance materials commonly used – manganese oxide, thereby forming such ultrafast super capacitor electrode. So-called pseudo-capacitors, in fact, is a supercapacitor, the electrode surface by the reaction of stored energy, than its performance (or referred to as an electric double layer capacitor EDLC) having a super capacitor stores energy like a battery mainly by electrostatic mechanisms . Yat Li also said: \”The problem is that the pseudo-capacitors, when the increaseThe thickness of the electrode, due to the structure of the slow diffusion of ions, the capacitance drops rapidly. Therefore, the biggest challenge we are facing is how to without sacrificing the quality of their units to increase the quality of pseudo load capacitor material at the same time or volume of the energy storage capacity. \”For the above challenges, new research Yat Li indicated that they have made a breakthrough in the balance pseudo capacitors mass loading and capacitance aspects. That is the researchers were able, without compromising performance, will improve the quality of load per cm 100 mg of the record level of manganese oxide, and for the purposes of the current commercial equipment, the average mass loading of about 10 milligrams per square centimeter. most importantly, the quality of the surface with the load capacitance and the manganese oxide electrode thickness increased linear and each gram capacitance (gravimetric capacitance) remained almost unchanged. this suggests that, even in such a high quality load, performance ion diffusion electrode is also not limited. the first author of the paper Bin Yao is the University of California, Santa Cruz a graduate student in the laboratory of Professor Lee Adams Angeles, he explained that the traditional business of manufacturing supercapacitor electrode material coating will be applied to a thin layer of a thin metal sheet as a current collector. However, with the increase in coating thickness degrade performance, so the method using a plurality of sheets are stacked to build the capacitor, but since the metal collector distributed in each layer, which not only increases the overall weight, but also increases the cost of the material .Yao also said: \”With our approach, we do not need a stack as we can at the same time, without sacrificing performance by making the electrode thicker to increase the capacity. \”Specifically, the researchers were able to increase the electrode thickness of 4 mm, without any loss of performance. And, they bore having a periodic electrode structure, which not only enables the uniform deposition of material, and an effective ion diffusion can be charged the discharge of which is printed by the 3D structure of the lattice rod constituting a cylindrical graphene airgel. in addition to the lattice structure of the hole itself is a porous rod was then electrodeposited manganese oxide to graphene aerogels glue lattice. \”the key innovation is the use of 3D printing research to make reasonable structure designed to provide a carbon scaffold to support the pseudo-capacitive material,\” Li said, \”these findings demonstrate the use of 3D printing manufacturing an energy storage device new method. \”Supercapacitor device graphene airgel made of manganese oxide / electrode shows good cycling stability at 20,000 charge and discharge cycles can still maintain more than 90% of the initial capacitance. 3D printing graphene airgel electrodes also has significant flexibility of design, because the 3D printer technology can be any shape desired form suitable apparatus. And LLNL developed graphene-based inks can be printed with ultra-high surface area, lightweight properties, flexibility and excellent conductivity.