Abstract:

In order to improve the working voltage of electrochemical capacitors, LiNi_0.5Mn_1.5O₄(LNMO) was employed as the positive electrode material and activated carbon(AC) was used as the negative electrode material for the asymmetric electrochemical capacitors and the optical conditions was explored. Enhancing the mass ratio of AC/LNMO and the voltage ranges could both increase the discharge capacity and energy density. At the AC/LNMO mass ratio of 4 and in the 0~3 V voltage range, 97.5% capacity retention was achieved after 700 cycles at current density of 1×10^-3 A/cm². Three-electrode system and electrochemical impedance spectroscopy were applied to explore the degradation of AC anode, and we also analyzed its influence in the AC/LNMO asymmetric capacitors.

Key words: LiNi0.5Mn1.5O4, activated carbon, electrochemical capacitors, degradation