High performance asymmetric V2O5–SnO2 nanopore battery by atomic layer deposition

Abstract

Here we report the high performance and cyclability of an asymmetric full cell nanopore battery, comprised of V₂O₅ as the cathode and prelithiated SnO₂ as the anode, with integrated nanotubular Pt current collectors underneath each nanotubular storage electrode, confined within an anodized aluminium oxide (AAO) nanopore. Enabled by atomic layer deposition (ALD), this coaxial nanotube full cell is fully confined within a high aspect ratio nanopore (150 nm in diameter, 50 μm in length), with an ultra-small volume of about 1 fL. By controlling the amount of lithium ion prelithiated into the SnO₂ anode, we can tune the full cell output voltage in the range of 0.3 V to 3 V. When tested as a massively parallel device (∼2 billion cm⁻²), this asymmetric nanopore battery array displays exceptional rate performance and cyclability: when cycled between 1 V and 3 V, capacity retention at the 200C rate is ∼73% of that at 1C, and at 25C rate only 2% capacity loss occurs after more than 500 charge/discharge cycles. With the increased full cell output potential, the asymmetric V₂O₅–SnO₂ nanopore battery shows significantly improved energy and power density over the previously reported symmetric cell, 4.6 times higher volumetric energy and 5.2 times higher power density – an even more promising indication that controlled nanostructure designs employing nanoconfined environments with large electrode surface areas present promising directions for future battery technology.