High performance lithium-ion capacitors based on LiNbO3-arched 3D graphene aerogel anode and BCNNT cathode with enhanced kinetics match

High energy density remains difficult to achieve using current lithium ion capacitors (LICs) because of the mismatch of kinetics between the capacitor-type cathode and battery-type anode. To enhance the kinetic match, a graphene aerogel (GA) supported LiNbO3 nanoparticles (LiNbO3@GA) 3D conductive network is configured as a novel anode as well as a boron carbonitride nanotube (BCNNT) as cathode for LICs. Kinetics analysis of LiNbO3@GA anode and BCNNT cathode are conducted to further investigate the cation/anion storage behavior. Benefiting from the high pseudocapacitive contribution of LiNbO3 and the appealing features of 3D conductive framework, the LiNbO3@GA anode demonstrates enhanced kinetic properties and high-rate pseudocapacitive behaviors. Anion storage from both surface-controlled pseudocapacitive reaction and diffusion-limited intercalation/deintercalation reaction in BCNNT electrode enables the cathode to exhibit fast charge-discharge capability, which greatly reduces the kinetic mismatch between cathode and anode. The assembled LiNbO3@GA//BCNNT LIC delivers the maximum energy density of 148 Wh kg(-1) at the power density of 200 W kg(-1) with a desirable cycling stability (82% after 7000 cycles). This strategy exploits a new type of material and widens the path for pseudocapacitive advanced high-rate devices in energy storage area.