Lithium Ion Capacitors in Organic Electrolyte System: Scientific Problems, Material Development, and Key Technologies

Abstract

Lithium ion capacitors (LICs), which are hybrid electrochemical energy storage devices combining the intercalation/deintercalation mechanism of a lithium‐ion battery (LIB) electrode with the adsorption/desorption mechanism of an electric double‐layer capacitor (EDLC) electrode, have been extensively investigated during the past few years by virtue of their high energy density, rapid power output, and excellent cycleability. In this review, the LICs are defined as the devices with an electrochemical intercalation electrode and a capacitive electrode in organic electrolytes. Both electrodes can serve as anode or cathode. Throughout the history of LICs, tremendous efforts have been devoted to design suitable electrode materials or develop novel type LIC systems. However, one of the key challenges encountered by LICs is how to balance the sluggish kinetics of intercalation electrodes with high specific capacity against the high power characteristics of capacitive electrode with low specific capacitance. Herein, the developments and the latest advances of LIC in material design strategies and key techniques according to the basic scientific problems are summarized. Perspectives for further development of LICs toward practical applications are also proposed.

Controlled Design of Well‐Dispersed Ultrathin MoS2 Nanosheets inside Hollow Carbon Skeleton: Toward Fast Potassium Storage by Constructing Spacious “Houses” for K Ions

“…The series of b ‐values, which are closer to 1.0, indicates the dominant capacitive‐controlled process of the ED‐MoS 2 @CT anode. Quantitatively, the total current response can be separated by the follow equation: i ( V ) = k 1 v + k 2 v 1/2 , where k 1 v denotes the capacitive contribution process and k 2 v 1/2 denotes the diffusion‐controlled process . Figure j shows a separation of capacitive contribution from the entire CV profile at 0.8 mV s −1 .…”

Recent Advances and Challenges of Two‐Dimensional Materials for High‐Energy and High‐Power Lithium‐Ion Capacitors

“…The obtained LICs delivered improved energy density (> 20 Wh kg À 1 ) while maintaining long cycle life (over 5000 cycles) and high rate capability (90 % capacity retention at a high rate of 10 C). [8][9] It is worth noting that, in principle, a capacitive asymmetric capacitor based on a pseudocapacitive electrode and an EDLC-type electrode is also named as LICs. [8] The former generally presents two working mechanisms depending on the position of different electrodes.…”

“…Besides, internal-parallel configurations show a complex electrochemical charge storage process with both Daniell-type and rocking-chair mechanisms. [8][9] It is worth noting that, in principle, a capacitive asymmetric capacitor based on a pseudocapacitive electrode and an EDLC-type electrode is also named as LICs. [6] As the determined factor for the electrochemical performance of LICs, various key electrode materials have been explored.…”

Thermally Durable Lithium‐Ion Capacitors with High Energy Density from All Hydroxyapatite Nanowire‐Enabled Fire‐Resistant Electrodes and Separators

“…Lithium-ion capacitors (LICs, also called as lithium-ion hybrid supercapacitors) would represent a realistic opportunity, in terms of combining the complementary features of SCs and LIBs with both high power density and energy density. [22][23][24][25][26][27] Generally, a LIC can be constructed from a battery-type anode and a supercapacitor-type cathode with a lithium-salt-containing electrolyte. So far, a wide variety of configurations including Li 4 Ti 5 O 12 (LTO), [28] TiO 2 , [29,30] V 2 O 5 , [31] Nb 2 O 5 , [32] and Si-based anodes [33] as well as the activated carbon (AC), [29] carbon nanotubes, [30] graphene, [34] and metal-organic frameworks-derived carbon nanostructures based cathodes have been explored.…”