Both 3D MC/carbon hybrids and 2D MXenes have been attracting great attention in the ES field (single-function batteries and SCs) due to their high electrical conductivity, large
surface area, porous/open structure, thermal stability and tunable redox states.[16,17] They will be pioneering building blocks to produce efficient TEHES.
NOVELTY:
- NEW advanced electrode nanomaterials for TEHES.
- THE FIRST TEHES built on textile substrates: except from our filed patent,[E] all reported TEHES are of plastic.
- New design concept for TEHES: assembly of 2 electrodes with different composition (asymmetric design) FOR THE FIRST TIME.
- Use of recyclable textile fabrics obtained from industry by-products FOR THE FIRST TIME as GREEN substrates in TEHES.
MAIN TARGETS:
1) Efficient all-in-one TEHES textiles with architecture geometries supported on numerical simulations.
2) Pilot-scale production of the TEHES & integration in a fully-functional e-garment.
3) Identification of a roadmap towards commercial exploitation.
TASK 1 consists on the preparation & characterization of novel 3D hybrids of 2D MC nanosheets supported on carbon NMs (MWCNTs and graphene). The hybrids will be produced by
in situ functionalization of the carbon NMs with MCs through eco-friendly scalable coprecipitation and hydrothermal processes developed by LAQV or adapted from literature (T1.3).
[B,18,19] 2D MCs have large surface area, superior electrochemical characteristics and electrical conductivity over their metal oxide counterparts. Nevertheless, they tend to
aggregate.[20] MWCNTs and graphene are remarkable carbon NMs with excellent mechanical properties, lightness, conductivity and large surface area. The hybridization of 2D MCs
with carbon NMs in single 3D MC/carbon hybrids combining redox properties, electrical and thermal conductivity will allow achieving TEHES with synergistically-enhanced thermal EH
and ES performance.
Special attention will be given to MWCNTs due to their high-quality at low cost ($1/g).[21] Carbon NMs will be oxidized or doped with heteroatoms by wet-chemical processes and
ball milling (T1.2)[22,23] for stronger chemical bonding of MCs.
The target 2D MCs are non-toxic binary and ternary AxB1-xSy (A,B=Mn,Fe,V,W,Mo,Ni,Zn,Co).(T1.1) Special attention to OEKO-TEX textile regulations will be given to ensure the
safety of the textile product for human health.
Hydrophilic 2D MXenes with different chemical composition (Ti1+nCnTx; n=1-3) and flake size will be supplied by their inventor, Prof. Gogotsi, Drexel Univ@USA (T1.4) through a
recently established collaboration. 2D MXenes are emerging materials with remarkable mechanical, chemical, electrical and TE characteristics.[24]
In TASK 2, the 3D MC/carbon hybrids, carbon NMs and 2D MXenes will be incorporated in fabrics to produce efficient thermally-chargeable bi- and monocomponent electrodes,
respectively. Three strategies will be used: 1) dyeing (T2.1); 2) screen-printing (T2.2) and b) spray-painting (T2.3). These routes are scalable, cost-effective and compatible with the
technologies that exist in textile industry, which will accelerate the technology transfer and scale-up.
The previous preparation of stable NM dispersions and printing inks is crucial to achieve uniform coatings and high substrates adhesion. The team has large expertise in this field.[AE,
8,25,26] Water-based dyeing dispersions will be produced by sonication of aqueous solvents, NMs and dispersing agents. The printing inks will be prepared using water/organic
solvents, binders, NMs and dispersants; they should have viscosity of ~10 mPa s to ensure high resolution and drying kinetics.
The substrates will be cotton, polyester and polyamide, their blends and mixtures with elastane.
In:
1) DYEING: exhaustion and foulard impregnation will be used.[23]
2) SCREEN-PRINTING will be used to design textile electrodes with specific patterns (T2.3, smaller dimensions and thickness of few hundred micron.[8]
3) SPRAY-PAINTING: production of fully-coated textile electrodes and with tailored-design patterns (T2.4). It is fast and highly versatile being suitable to coat larger surfaces and
design complex shapes.[8]
In TASK 3 TEHES textiles with simultaneously-enhanced EH and ES outputs and flexibility will be produced by assembling electrodes with similar or different composition in
symmetric and asymmetric configurations and non-toxic solid-gel electrolytes.
Different asymmetric TEHES will be produced to maximize the EH and ES performance: i) carbon-coated electrode//hybrid MC/carbon electrode; ii) MXene-coated electrode//carboncoated
or hybrid MC/carbon electrode; iii) two distinct hybrid electrodes.
Solid-gel polymer electrolytes are of prime importance since they are less toxic, can be stretchable and have greater reliability in a wider temperature range.[27] The selected
polyelectrolytes will be hydrogel polymers (e.g., PVA, carboxymethyl cellulose) doped with redox mediators (e.g., potassium hexacyanoferrate, hydroquin |