7. Atomic Layer Deposited Supercapacitor Electrodes

Atomic layer deposition (ALD), an advanced and modified version of chemical vapor deposition (CVD), has become one of the state-of-the-art technologies for depositing high quality thin films with precise thickness control over a variety of planar as well as complex three-dimensional structures. In contrast to CVD, the thin film growth via ALD involves chemical reactions between the precursor (in gaseous phase) and surface species in a self-limiting fashion, which allows extremely uniform deposition of desired materials on virtually any substrate feature. Although the materials presently being used in energy storage devices are performing close to their theoretical limits in bulk form, the recent developments in nanotechnology allow for extracting novel properties from their nanosized forms. This poses ALD as an ideal technique for designing high-performance supercapacitor (SC) electrode materials possessing fast charge transfer kinetics and improved energy and power delivery with better cycling and rate performances. This chapter presents a summary of the recent advances on the use of ALD to design SCs with desirable structures and the ensuing properties. In addition, the present challenges and potential opportunities for future exploration of ALD to achieve desired electrochemical performance of next generation SCs are also pointed out.