High energy lithium ion capacitors using hybrid cathodes comprising electrical double layer and intercalation host multi-layers
By Lee, Sang Ho; Huang, Chun; Grant, Patrick S.
Published in Energy Storage Materials
Energy Storage Materials
2020
Abstract
The ability to recharge and to deliver high capacity quickly is required for the next generation of lithium ion storage technologies, especially for pure electric vehicles. A new type of hybrid positive electrode for lithium ion capacitors is investigated that comprises discrete layers of high power capacitive activated carbon and high capacity insertion-type LiFePO4, with the aim of boosting energy density towards that of a lithium ion battery while preserving capacitor-like power capability over thousands of charge/discharge cycles. The electrochemical performance of these hybrid electrodes was investigated both as a function of the LiFePO4 weight fraction (its thickness in the multi-layered electrode arrangement) and its location within the multi-layer. The best performing hybrid positive electrode architecture delivered an attractive balance of an energy density of 90 Wh/kg and a power density of 15 kW/kg in a full lithium ion capacitor configuration, which outperformed other combinations of the same materials. The ability to produce a double-sided configuration of the hybrid layered electrode over 20