Nanostructured spinel LiNi 0.5 Mn 1.5 O 4 as new insertion anode for advanced Li-ion capacitors with high power capability

We demonstrate a novel Li-ion hybrid electrochemical capacitor (Li-HEC) assembled using 1D nanofibers of a high voltage spinel insertion electrode (LiNi0.5Mn1.5O4) and an activated carbon (AC) counter electrode in an organic electrolyte. A scalable electrospinning technique was employed to produce 1D nanofibers of the high voltage spinel electrode. Structural and morphological features of the nanofibers were studied using various characterization techniques. Performance of spinel and AC electrodes were evaluated in half-cell configurations with metallic Li. A Li-HEC assembly with optimized mass loading delivered a maximum energy density of ~19 Wh kg−1 while retaining ~81% of the initial value after 3000 cycles.