High Performance Asymmetric V2O5-SnO2 Nanopore Battery By ALD

Abstract

An array of nanobatteries, each self-aligned and fully confined within a single nanopore, provides an effective testbed for the rate performance and cyclability limits of nanostructured storage devices. With atomic layer deposition (ALD), we have previously synthesized and evaluated such structures in a symmetric configuration, comprised of nanotubular V2O5 electrodes as both anode and cathode and electrolyte confined within anodic aluminum oxide (AAO) nanopores. Each nanopore battery has ultra-small volume (~1fL) and shows superior performance when tested as massively parallel device (~2billion/cm2). [i] However, an asymmetric full cell configuration with a low voltage anode material has not been explored yet. Here we report an asymmetric full cell nanopore battery, comprised of V2O5 as cathode and prelithiated SnO2 as anode, with integrated nanotubular Pt current collectors underneath each nanotubular storage electrode. Also enabled by ALD, this coaxial nanotube full cell is fully confined within the high aspect ratio nanopore (150nm in diameter, 50um in length). By controlling the amount of lithium ion prelithiated into SnO2 anode, we can tune full cell output voltage in the range of 0.3V and 3V. This asymmetric nanopore battery array displays exceptional rate performance and cyclability. When cycled between 1V and 3V, it has capacity retention of approximately 73% at 200C rate compared to 1C, with only 2% capacity loss after more than 500 charge/discharge cycles. With increased full cell output potential, the asymmetric V2O5-SnO2 nanopore battery shows significantly improved energy and power density. This configuration presents a more realistic test - through its asymmetric (vs symmetric) configuration – of performance and cyclability in nanoconfined environment. [i] Liu, C.; Gillette, E. I.; Chen, X.; Pearse, A. J.; Kozen, A. C.; Schroeder, M. A.; Gregorczyk, K. E.; Lee, S. B.; Rubloff, G. W., An all-in-one nanopore battery array. Nature Nanotechnology 2014, 9 (12), 1031-1039.