The structure realized is basically a capacitor, with a storage capacity of the charge which is formed between a pattern of gold nanowires coated with manganese dioxide and suspended in a medium electrolyte. The use of nanowires enables it to offer a greater charge storage compared to films while the same material. The dimensions are a thousand times less than those of a human hair, it is also characteristic that combines to a high conductivity and a wide surface for the storage and transfer of electrons.
Previous research works have shown how the gold nanowires were extremely fragile and do not respond adequately to repeated charging and discharging operations. Inserted in a lithium-ion battery of a normal structure will expand and contract, showing the long term problems of fracturing.
The researchers were able to solve this problem by covering the nanowire with manganese dioxide and placing them in an electrolyte composed of a gel-like Plexiglas (polymethyl methacrylate and lithium percolrato), which showed reliability and convincing resistance. The specimen thus obtained was tested with charge / discharge operations for 200,000 times in the space of three months, without that showed no loss of capacity or power and without fracturing the nanowires.
Reginald Penner, lead author of the publication of Letters Energy, commented: "It 's amazing, because these things usually stop working after five, six or seven thousand cycles at most." The structure used by the researchers purposely made use of extra long nanowires, compared to their thickness, just to reveal or amplify the effects of any malfunction. The researchers argue that the gel interacts with the metal oxide in the battery offering flexibility, avoiding fracturing problems.
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