Ultrafast Carrier Transport through an Advanced Thick Electrode with a High Areal Capacity for Aqueous Lithium-Ion...

Thick electrode design holds great promise to render the aqueous lithium ion battery more cost effective by boosting the packing density of the electroactive materials to enhance the energy delivery at the device level. However, a thick electrode faces the concomitant challenge of the sluggish transport of electrons and, importantly, the Li ions. To address this issue, numerous 3 D shortcuts that include a conductive percolation network and well-interconnected mesoporous channels were established in the 330 μm thick V₂ O₅ ⋅H₂ O/CC monolithic electrode developed here. In this way, electron transfer and ion transport were favored, which accounts for the outstanding charge-storage capacity that exceeded 2 mA h cm^-2 and the exceptional energy and power densities of 1.38 mW h cm^-2 and 34.1 mW cm^-2 , respectively, measured at the electrode and the device scale within a short subhour timeframe. Such a remarkable high rate performance is better than that of electrodes reported previously for commercial lithium-ion microbatteries, advanced aqueous batteries, and state-of-the-art supercapacitors designed for high-power applications.