Study On Lithium/Sodium Storage Performance Of High-capacity Organic Cathode Material Calix[6] Quinone In Ionic Liquids

The widespread use of portable electronic products in daily life promotes the continuous development of secondary batteries,but the low capacity,high costs,and environmental pollution of inorganic electrode materials have restricted their further improvement.Compared with inorganic electrode materials,organic electrode materials have higher theoretical specific capacity,rich resources,and strong structural design.They are the most advantageous electrode materials in the next generation of green batteries.Among them,the new quinone electrode material calix[6]quinone（C6Q）has 12 active sites,a theoretical specific capacity of up to 446 m Ah g^-1,and excellent lithium/sodium storage performance,which is a promising electrode material.However,it is easy to dissolve in organic electrolytes,resulting in poor cycle stability.Therefore,this article improved the lithium/sodium storage performance of C6Q by optimizing the electrolyte system and using ionic liquids to reduce the capacity decay rate of C6Q.In this article,the charge and discharge mechanism of C6Q has been discussed.And the LiTFSI/[PY13][TFSI]lithium ion electrolyte,Na TFSI/[PY13][TFSI]and Na Cl O₄/[PY13][TFSI]sodium ion electrolyte were prepared.C6Q was used as the cathode material,and ionic liquid was used as the electrolyte.The lithium/sodium storage performance of the C6Q in ionic liquid electrolyte was studied.（1）C6Q was successfully synthesized by coupling,oxidation and reduction.And the smaller Lowest Unoccupied Molecular Orbital and energy gap difference of C6Q were calculated by density functional theory.The lithium/sodium ionic liquid electrolyte was prepared,and the conductivity test showed that the lithium salt concentration was 0.3 M,the conductivity of the lithium ionic liquid electrolyte reached the maximum.（2）The lithium storage performance of C6Q in 0.3 M LiTFSI/[PY13][TFSI]electrolyte had been systematically studied.The results showed that the ionic liquid electrolyte can not only improve the cycle stability but also improve the rate performance of C6Q compared with the ordinary liquid electrolyte.And the system has low impedance and good lithium ion diffusion ability.The simulated lithiation potential of C6Q was obtained through DFT calculation,and the calculated results were supported by the actual test results,which proved the correctness of the actual test results.（3）The sodium storage performance of C6Q in 0.3 M Na TFSI/[PY13][TFSI]and Na Cl O₄/[PY13][TFSI]electrolytes had been systematically studied.The results show that,compared with the ordinary electrolyte,the two ionic liquid electrolytes have improved C6Q cycle stability,rate performance and electrode kinetics.The cycle stability of C6Q was significantly improved in Na TFSI/[PY13][TFSI]electrolyte,while the coulombic efficiency was more stable（close to 100%）in Na Cl O₄/[PY13][TFSI]electrolyte.