Multidimensional Materials and Electrode Architectures for High-Rate Hybrid (Faradic+Capacitive) Energy Storage
Drexel University & Jilin University
Abstract: Electrical energy storage (EES) plays a vital role in daily life because of our dependence on numerous electronic devices that require mobility . Moreover, with miniaturization of electronics, penetration of wireless devices into our homes and clothes, wide use of sensor networks and widely anticipated “internet of things”, there is a major effort to develop miniature, but powerful EES devices. There is also a need for large-scale and inexpensive EES for grid and transportation. While there are thousands of papers on batteries and supercapacitors, new concepts must be formulated that will lead to a new generation of sustainable, affordable and safe EES technologies that will approach the theoretical limits for electrochemical storage and deliver electrical energy rapidly and efficiently. This presentation will address the cutting edge of EES, showing approaches to overcome diffusion limitations, which make current batteries slow and short-lived, by using capacitive EES principles (surface redox and fast intercalation processes) . Two-dimensional (2D) materials with a thickness of a few nanometers or less can be used as single sheets due to their unique properties or as building blocks, to assemble a variety of structures [2[. Nonplanar architectures and redox materials, such as 2D transition metal carbides and nitrides (MXenes ) designed to increase the volumetric energy density of an electrode and eliminate/minimize the use of separators and current collectors will be reviewed. Oxygen or OH terminated MXenes, such as Ti3C2Ox, have redox capable transition metals layers on the surface and offer a combination of high electronic conductivity with hydrophilicity, as well fast ionic transport, offering charge-discharge time down to 10 ms . Future research directions will be outlined with the goal of defining a new generation of EES materials/devices whose energy storage characteristics represent true hybridization of batteries and electrochemical capacitors.