Lithium-Ion Capacitors with TME Lithium Powder Pre-embedded for Tetramethylethylene Applications

With tetramethylethylene (2,3-Dimethyl-2-butene, TME) as the polymer source, lithium powder (Li) was immersed to obtain highly stable lithium powder (TME-Li) coated with poly 2,3-Dimethyl-2-butene. It was pre-embedded into an electrode sheet with an intermediate carbon microsphere (MCMB)/multi-wall carbon nanotube (MWCNT)/super carbon black (SP) composite material as a negative electrode and assembled into a lithium-ion capacitor (LIC). Scanning electron microscopy and intelligent Fourier transform infrared spectroscopy were used to analyze lithium powder and electrode sheets scientifically. In addition, constant current charge-discharge (GCD) and electrochemical impedance spectroscopy were also used to analyze the electrochemical properties of the LIC. The results show that embedded TME-Li can improve the electrochemical performance of capacitors efficiently. When the current density is 50 mA g(-1), the specific capacitance can reach 69.09 F g(-1). Within the current density range of 50-700 mA g(-1), the maximum power density is 1.02 kw kg(-1), and the energy density is as high as 91.14 Wh kg(-1). After 4000 constant current charge and discharge cycles, the capacitance retention rate is still above 83%, showing good electrochemical performance.