Electrospun Nd3+-Doped LiMn2O4 Nanofibers as High-Performance Cathode Material for Li-Ion Capacitors

Electrospun high-voltage spinel-typeLiNd(0.01)Mn(1.99)O(4) nanofibers (LNdMO NFs) were successfully prepared through the electro-spinning technique. The thermal behavior of the electrospun precursor fibrous mat was assessed by thermogravimetric/differential thermal analysis. The crystallite structure and phase purity of Nd3+-doped LiMn2O4 was confirmed by X-ray diffraction studies. The chemical structure of the electrospun LNdMO NFs was characterized by Raman spectroscopy studies. The morphology of the nanofibers was examined by using field-emission scanning electron microscopy. A Li-ion capacitor (LIC) coin cell was fabricated by using high-voltage insertion LNdMO NFs as the cathode and black pearl carbon as the anode with electrospun PVdF membrane containing 1 M LiNO3 as the separator and electrolyte. The electrochemical performance of the assembled LIC coin cell was characterized by using cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. The LIC was capable of operating over wide potential window of 1.6 V with excellent capacitance retention of 86% even after 2500 continuous galvanostatic charge-discharge cycles at a constant current density of 1 Ag-1. Furthermore, LIC delivered an energy density of 17 Whkg(-1) and a power density of 397 Wkg(-1). Moreover, these results show that Nd3+-doped LiMn2O4 NFs can be considered a promising electroactive cathode material for LICs.