High energy lithium ion capacitors using hybrid cathodes comprising electrical double layer and intercalation host multi-layers

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 × 20 cm 2 was demonstrated, confirming the potential scalability of layer-by-layer manufacture.

Multidimensional Dual-Carbon Skeleton Network Confined MnOx Anode Boosting High-Performance Lithium-Ion Hybrid Capacitors

“…The energy/power density indicators of LIHCs are shown in Figure g; they can reach up to 151 Wh kg –1 at 196.6 W kg –1 and maintain 42.6 Wh kg –1 at an ultrahigh power density of 21.9 kW kg –1 , which are the characteristics of integrated high power and high energy. Furthermore, the energy/power density indicators of LIHCs are superior to many recently reported LIHCs. − In terms of cycling stability, the assembled LIHCs deliver excellent cycle stability with a capacity retention of 79% over 1200 cycles at 1 A g –1 (Figure d). Interestingly, a “BUCT” pattern composed of dozens of yellow LEDs can be easily lighted up by these LIHCs (illustrations in Figure g) after fully charged at 1 A g –1 , demonstrating the promising application potential.…”

Smart Multi‐Layer Architecture Electrodes for High Energy Density Lithium‐Ion Capacitors

“…The best location of the best performing 2 μm Si within the through‐thickness multi‐layer was then explored, suggesting that locating the Si layer closer to the separator/positive electrode (reversely further away from the current collector), in principle, allows for the shortest pathway for active ions traveling towards and from high capacity Si, and thus is advantageous in terms of lithiation reaction kinetics. Currently, hybrid electrode structures were also developed by spray coating of capacitive AC (YP‐50F, YP) and insertion‐type LiFePO 4 (LFP) into otherwise multi‐layers [14] . Performance balances between power (YP) and capacity (LFP) were then thoroughly studied as a function of weigh fractions and spatial variations of discrete LFP layers, with the intention to take best advantage of composite electrode designs that outperform a configuration with LFP “randomly scattered” across YP.…”

“…CV measurements were carried out using Autolab M204. The theoretical capacity of LTO, Si and LFP was assumed to be ~175 mAh/g, [41] ~4000 mAh/g [13] and ~170 mAh/g, [14] respectively.…”

“…Currently, hybrid electrode structures were also developed by spray coating of capacitive AC (YP-50F, YP) and insertion-type LiFePO 4 (LFP) into otherwise multi-layers. [14] Performance balances between power (YP) and capacity (LFP) were then thoroughly studied as a function of weigh fractions and spatial variations of discrete LFP layers, with the intention to take best advantage of composite electrode designs that outperform a configuration with LFP "randomly scattered" across YP.…”

Multi-layered composite electrodes of high power Li4Ti5O12 and high capacity SnO2 for smart lithium ion storage

“…Given the good fit, it is possible to estimate the effective lithium ion mobility for the SnO2 part of the electrode using the Randles-Sevcik equation. [46,47] Ip = 0.4463n FAC0(nFυMLi/RT) 1/2 (1)…”