Integrated supercapacitor with self-healing, arbitrary deformability and anti-freezing based on gradient interface structure from electrode to electrolyte

Recent Trends in Supercapacitor Research: Sustainability in Energy and Materials

“…Due to such interface between the surface of PANI‐based electrodes and GPE, which did not prevent reversible redox reactions involving VO 3− and Fe 2+ , the SC showed a high Cs of 441.8 mF cm −2 (Figure 24 h), an energy density of 63.1 μWh cm −2 and stability under long‐term cycling. This SC proved to be able to operate even at low temperatures (−20 °C) and demonstrated the ability to retain more than 89 % of the specific capacitance after 6 cycles of full cut/self‐recovery [200] …”

“…Gel‐polymer materials based on the well‐known PVA are often used as self‐healing electrolytes, to which acids, salts or alkalis are usually added to improve ionic conductivity (PVA‐H 2 SO 4 , [81,215] PVA‐glycerin(Gly)‐H 2 SO 4 , [183] PVA‐HNO 3 , [166] PVA‐4‐(CPBA)‐Ca 2+ , [176] PVA‐Agar‐GO‐[EMIM]BF 4 ‐Li 2 SO 4 , [178] ). However, developments in the field of self‐repairing electrolytes are not standing still but are moving towards more complex multicomponent systems with unique cross‐linking structures [199,200] . A multicomponent gel‐polymer electrolyte (PAA/C18/H 3 PO 4 /NH 4 VO 3 ‐FeSO 4 ) based on hydrophobic stearyl acrylate (C18) copolymerized with hydrophilic acrylic acid (AA) to create a primary network via hydrophobic association was proposed [200] .…”

“…This SC proved to be able to operate even at low temperatures (À 20 °C) and demonstrated the ability to retain more than 89 % of the specific capacitance after 6 cycles of full cut/selfrecovery. [200] There are few studies concerning the development of electrode materials capable of self-healing and fully self-healing SCs. [11,163,166,176,199,200] Various polymeric materials are used to create electrode materials as self-healing backbones, such as polyaniline (PANI, [183,200] PANI-3-Maba [176] ), poly(3,4-ethylenedioxythiophene) (PEDOT:PSS-rGO, [199] MWCNTs-graphene-PEDOT: PSS [166] ), polyacrylamide and polypyrrole (Fe 3 O 4 @Au-PAM-PPy) [163] ).…”

“…[199,200] A multicomponent gel-polymer electrolyte (PAA/C18/H 3 PO 4 /NH 4 VO 3 -FeSO 4 ) based on hydrophobic stearyl acrylate (C18) copolymerized with hydrophilic acrylic acid (AA) to create a primary network via hydrophobic association was proposed. [200] Polyacrylic acid (PAA), containing a large number of carboxyl groups, provided the formation of numerous hydrogen bonds. In addition, when the obtained hydrogel backbone was impregnated with H 3 PO 4 /NH 4 VO 3 -FeSO 4 solution, the carboxyl groups of polyacrylic acid were coordinated by the polyvalent metal ions in its composition, leading to even greater adhesion of polymer chains (Figure 24a).…”

“…[11,[191][192][193] Due to their long-term stability, high power density, ease of miniaturization and flexibility, SCs have been recognized as promising devices for this purpose. [10,191,194] In recent years, great progress has been made in the development of smart supercapacitors, which have additional properties that are not characteristic of conventional SCs, such as flexibility and stretchability; [10,13,191,195,196] the ability to self-charge through various energy sources (including energy produced by the organism itself during respiration and movement); [195][196][197][198] the ability to self-heal structure and performance after damage or deformation; [11,163,166,176,199,200] electrochromism, which allows us to assess the degree of charge of the device; [13,99,102,201,202] and integration with sensors, [177,[203][204][205][206] as well as biocompatibility and biodegradability at the end of life, designed to reduce e-waste and environmental pollution [207][208][209] (Figure 16). The development of such systems will not only help meet people's energy needs but also make life more comfortable and mobile.…”