The prospect of developing energy storage materials with the energy density of batteries and the power density and cycle life of electrical double-layer capacitors is an exciting direction that has yet to be achieved. With such materials there is the promise of charging in minutes, much faster than batteries, without compromising the amount of charge storage. Our research has focused on so-called pseudocapacitive materials in which faradaic reactions are sufficiently rapid so that the electrochemical features are similar to those of an electrical double-layer capacitor, but with significantly higher levels of energy storage because of the redox reactions. Using Nb2O5 as a model system, we have established several criteria for identifying materials that exhibit pseudocapacitor-like properties and retain high energy density at high rates of charge/discharge. The properties of batteries and hybrid devices incorporating pseudocapacitive electrodes will be presented. The design of electrode architecture offers another route for achieving high rate energy storage. We demonstrate the design principles for non-planar configurations using a solid-state 2.5D battery consisting of a 3D LiFePO4 (LFP) post array and a planar, Li anode separated by an ionogel electrolyte. The rod array architecture provides high areal energy density while the high conductivity of the ionogel electrolyte enables power levels above 3 mW cm-2 to be achieved. To extend these concepts toward large format designs, we have developed 3D lattice configurations in which the LFP architecture is fabricated by direct ink writing. The areal energy density is determined by the thickness and number of LFP layers, leading to areal capacities above 3 mAh cm-2. The properties of the resulting solid-state 2.5D batteries will be presented.

Materials and architectures for high rate energy storage

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.