Li₄Ti₅O₁₂−TiO₂ Composite Coated on Carbon Foam as Anode Material for Lithium Ion Capacitors: Evaluation of Rate Performance and Self‐Discharge

Abstract

Li 4 Ti 5 O 12 -TiO 2 (LTO-TO) composite is coated on carbon foam (CF) for anode of lithium ion capacitors (LICs). The resulting CF@LTO-TO electrodes with varied mass loadings of LTO-TO exhibit much improved rate performance compared to pristine LTO electrode. Specifically, asymmetric LICs based on activated carbon cathode and CF@LTO-TO anode (AC//CF@LTO-TO) with 25 wt% of LTO-TO delivers a specific capacity of 65 mAh g À 1 at 300 C. In addition, the selfdischarge rates of the LICs are evaluated. It is found that AC// CF@LTO-TO LIC with 45 wt% of LTO-TO shows much reduced self-discharge rate (open circuit voltage drops from 2.5 to 1.1 V in 144 hours) relative to AC//CF@LTO-TO with different LTO-TO mass loadings. The results of this study suggest that the introduction of TO in LTO anode can affect both the rate performance and the self-discharge behavior, which may be due to the fast faradaic reaction kinetic of TO and the rich LTO-TO grain boundary interfaces.

Reducing the Self-Discharge Rate of Supercapacitors by Suppressing Electron Transfer in the Electric Double Layer

“…[3][4][5][6][7][8] A few strategies have been attempted to date to suppress the selfdischarge of SCs based on proposed mechanisms including charge redistribution, faradaic reaction, and ohmic leakage. 6,[9][10][11][12][13][14][15][16] For instance, Black et al examined the effect of charge redistribution on the self-discharge of SCs and found that reduced charge redistribution can be achieved by increasing the charging duration and decreasing the charging current, 17 although this approach requires additional energy and longer charging time. Nematic liquid crystal (5CB, 4-n-pentyl-4′-cyanobiphenyl) 15,18 or nematic hybrid liquid crystal 19 have been introduced as additives to electrolytes to suppress the self-discharge of SCs via electrorheological effect.…”

Advanced and Emerging Negative Electrodes for Li-Ion Capacitors: Pragmatism vs. Performance

“…Furthermore, Zhu et al reported a nanocrystalline composite, LTO/TiO 2 /C, which was capable of delivering a discharge capacity of 88 mAh g −1 at 30 • C [43]. Using similar principles, Zouh et al utilized a carbon foam as a conductive matrix for a LTO-TiO 2 composite (CF@LTO-TO), studying the performance of the device and self-discharge at the same time [44]. The electrodes with high mass loading of LTO-TiO 2 composite (25 and 45 wt%) exhibited substantially improved rate performance compared to those with lower mass loadings.…”

Three-Dimensional Bi2S3 Nanoflowers with Built-In MXene Nanosheets for Reversible Lithium-Ion Storage with Enhanced Performance and Kinetics

“…As a promising anode material for LIBs, the Li 4 Ti 5 O 12 (LTO) anode has attracted a lot of attention due to its stable voltage plateau of 1.5 V vs Li/Li + , better cycling performance, high safety, easy fabrication, and low-cost precursors . However, due to its low theoretical capacity (175 mA h g –1 ) and high voltage (1.5 V), researchers are still in search of low-voltage and high-capacity anode materials.…”

“…5−11 As a promising anode material for LIBs, the Li 4 Ti 5 O 12 (LTO) anode has attracted a lot of attention due to its stable voltage plateau of 1.5 V vs Li/Li + , better cycling performance, high safety, easy fabrication, and low-cost precursors. 12 However, due to its low theoretical capacity (175 mA h g −1 ) and high voltage (1.5 V), researchers are still in search of lowvoltage and high-capacity anode materials. Therefore, Bi 2 S 3 is a suitable substitute for LTO as an LIB anode material due to its higher theoretical specific capacity (625 mAh g −1 ), low voltage (0.9 V), and reduced diffusion barrier.…”