High Energy Density Aqueous Li-Ion Flow Capacitor

High energy density Li-ion hybrid flow capacitors are demonstrated by employing LiMn2O4 and activated carbon slurry electrodes. Compared to the existing aqueous flow electrochemical capacitors, the hybrid one exhibits much higher energy densities due to the introduction of high capacity Li-insertion materials (e.g., LiMn2O4 in the present work) as the flowable electrode with asymmetrical cell configuration. A record energy density, i.e., 23.4 W h kg(-1) at a power of 50.0 W kg(-1) has been achieved for aqueous flow capacitors tested at static condition reported to date. A full operational Li-ion flow capacitor tested in an intermittent-flow mode has also been demonstrated. The Li-ion hybrid flow capacitor shows great promise for high-rate grid applications.