Convex and Concave Square Arrays of Vertical SnO2 Nanowire Bundles toward Lithium-Ion Storage Electrodes

We report on the convex and concave square arrays of tin dioxide nanowire bundles for use in rechargeable lithium-ion storage electrodes. The well-aligned and periodic patterns of the nanowire bundles were fabricated over current collectors by means of a photolithography process. The electrochemical properties, which were investigated by varying the pattern geometries of the nanowire electrodes, show that the convex and concave arrays lead to more improved charge/discharge dynamics in lithium-ion storage than the nonpatterned one. The empty spaces formed between the array patterns can facilitate the access of the liquid electrolyte to the electrode structures as well as the strain relaxation of electrode materials during repeated lithiation/delithiation processes. Interestingly, the convex square patterns promote more efficient ion transfer than the concave ones. To this end, the full-cell battery is successfully and explicitly demonstrated, which suggests that these tailored electrode platforms could stimulate scientific interest in the design and development of nano-wire-based electrode architectures.