研究人员称，有一种新的储能设备，可以同时具有高能量电池的特点以及快速充电电容器的特点。传统的EDLCs依靠液态或凝胶态电解质，在高温或低温的情况下，这种电解质将失效。
Rice的超级电容，用氧化的不导电的材料形成的纳米尺寸的固态包裹物（a solid, nanoscale coat of oxide dielectric material）完全取代电解质。
研究人员称，高容量超级电容器的关键是提供更大的表面积，使电子可以停留。这种新的设备通过使用大量直径为15-20纳米、高度为50微米的单碳纳米管（single-walled carbon nanotubes (SWNT)）形成的管束，增加了表面积，做到了这一点。（这种管束基本像一个地毯式阵列。）
这种阵列随后被使用在一个铜电极上（这种铜电极覆盖有黄金和钛材料形成的薄层），使用该阵列后，可以增加电子的附着力以及电气的稳定性。为了提高导电性能，这种纳米管束（主电极）被硫酸包围，用以提高其导电性能。随后，通过一种叫做原子层沉积的过程（atomic layer deposition (ALD)），用薄膜材料包裹电极，这种薄膜材料组成物有：氧化铝（不导电层）、掺有铝的氧化锌（aluminium-doped zinc oxide）（反电极(the counterelectrode)）。最后，顶端再使用镀银电极连通整个电路。
A new type of energy-storage device can combine the best qualities of high-energy batteries and fast-charging capacitors, researchers claim.
Crucially, the researchers at Rice University say it is robust and can operate in extreme environments, and so could potentially be integrated into the manufacture of panels in items such as satellites and electric vehicles.
Standard capacitors that regulate flow or supply quick bursts of power can be discharged and recharged hundreds of thousands of times. Electric double-layer capacitors (EDLCs), generally known as supercapacitors, are hybrids that hold hundreds of times more energy than a standard capacitor, like a battery, while retaining their fast charge/discharge capabilities.
But traditional EDLCs rely on liquid or gel-like electrolytes that can break down in very hot or cold conditions. In Rice’s supercapacitor, a solid, nanoscale coat of oxide dielectric material replaces electrolytes entirely.
The key to high capacitance is giving electrons more surface area to inhabit, the researchers say. For this, the new device relies on numerous bundles of single-walled carbon nanotubes (SWNT) 15–20 in nanometre in diameter and up to 50 microns long, essentially grown as a carpet-like array.
The array is then transferred to a copper electrode with thin layers of gold and titanium to aid adhesion and electrical stability.
The nanotube bundles (the primary electrodes) are doped with sulphuric acid to enhance their conductive properties; then they were covered with thin coats of aluminium oxide (the dielectric layer) and aluminium-doped zinc oxide (the counterelectrode) through a process called atomic layer deposition (ALD). A top electrode of silver paint completed the circuit.
‘Essentially, you get this metal/insulator/metal structure,’ said Cary Pint of Rice, who is the lead author of the published research. ‘No one’s ever done this with such a high-aspect-ratio material and utilising a process [such as] ALD.’
Pint said the supercapacitor holds a charge under high-frequency cycling and can be naturally integrated into materials. He envisages an electric car body that is a battery, or a microrobot with an on-board, non-toxic power supply that can be injected for therapeutic purposes into a patient’s bloodstream.