Preparation And Property Optimization Of Electrode Materials For Lithium Titanate-based Lithium Ion Capacitors

As a new energy storage element,lithium-ion capacitors inherit the advantages oflithium-ion batteries and double-layer capacitors.Due to different energy storage mechanism of electrode materials,it is a hot topic to solve the rapid intercalation and deintercalation of lithium ions in the process of high rate charge-discharge.In this work,the electrochemical performance of lithium ion capacitors is improved by adjusting the microstructure and adding conductive components in materials.The carbon-containing nanocrystalline LTO with zero strain and high specificcapacitance has higher specific capacitance and stability than the commercial LTO.The specific capacity of 2 C(1C=175 mAh/g)LTO-GC is 179 mAh/g in the three-dimensional bridge conductive networks of composite conductive agent GC-SP,and it still has high specific capacities,good electrochemical reversibility,high rate performance and low charge transfer internal resistance at the high rate of 40C.SACM with three-dimensional porous conductive networks is synthesized by attaching phenolic resin to carbon microspheres with SA.The surface area can reach2629 m~2/g and the total pore volume can reach 1.915 cm~3/g.Its maximum specific capacitance is 149 F/g at the current density of 0.2 A/g.the specific capacity can reach60 mAh/g and retention rate can reach 97%at the current density of 5 A/g.The optimum mass ratio can be obtained by assembling and testing capacitors with different mass ratios of positive and negative electrodes.The energy density of SACM//LTO-GC=3 capacitor can reach 65 Wh/kg at the current density of 0.1 A/g.The capacity retention rate is as high as 85%,after 500 cycles of discharge.