PDMS-encapsulated supercapacitor with an electrolyte being a liquid

A supercapacitor (SC) stores the energy basing on physical phenomena resulting in the formation of an angstrom-thick electrical double layer between the electrode surface and liquid electrolyte. Thanks to this, the SCs offer a long lifetime (up to about 104 hours)and - regarding such parameters as energy and power densities - they are located between fast electrolytic capacitors and slow batteries [1, 2]. Therefore, the SCs are considered as a power supply for many tiny devices [3]. However, the issue is how to preserve their impressive performance as they are encapsulated. One of the potential solutions is to encapsulate the SC components in silicon-based polymer, polydimethylsiloxane (PDMS), which constitutes the substitute for glass with additional properties – flexibility and easily shaping by so-called mold technique [4–6]. So far in most of the present works gel- or solid-type electrolyte has been used. Because of their higher viscosity - compared to the liquid electrolyte – there is a facile control over an encapsulation process. On the other hand, it can not guarantee the as fast flow of ions between the electrodes as a liquid electrolyte. In a consequence, the high-rate charging of the SC is diminished.