Polytetrafluoroethylene

Anti-17-estradiol antibody and 17β-estradiol were purchased from Abcam (Cambridge, UK). The Alexa fluor 488-conjugated goat anti-rabbit IgG (H + L) cross-adsorbed secondary antibody was purchased from Thermo Fisher Scientific (Massachusetts, USA). Cysteamine hydrochloride (≥99%), bovine serum albumin (BSA, ≥99%), phosphate-buffered saline (PBS, 1X), (3-aminopropyl)triethoxysilane (APTES, 99%), ethanol (EtOH, 99.8%), polytetrafluoroethylene (PTFE, 99%), perfluoro(n-butyltetrahydrofuran) (FC-40, 99%), and 1H,1H,2H,2H-perfluorodecyltriethoxysilane (97%) were purchased from Sigma Aldrich. A soda-lime glass substrate was bought from ISOLAB Laborgeräte GmbH. Ag and Au pellets (99.99%) were bought from iTASCO (Taewon Scientific Co., Ltd, Korea). Aqueous solutions were prepared using ultrapure water (Thermo Scientific Easypure II, Göteborg, Sweden) with a resistivity of 18.2 MΩ cm.

Alginic acid sodium salt from brown algae (Alg, medium viscosity), poly(vinyl alcohol) (PVA, M_w = 130,000, 99+% hydrolyzed), gelatin from porcine skin (Type A), poly(3,4-ethylenedioxythio phene):poly(styrene sulfonate) (PEDOT:PSS, 1.3 wt% dispersion in H₂O, conductive grade, 1 S/cm), polytetrafluoroethylene (PTFE), calcium chloride dihydrate (CaCl₂·2H₂O, assay ≥ 99.0%), barium chloride dihydrate (BaCl₂·2H₂O, assay ≥ 99%), aluminum chloride hexahydrate (AlCl₃·6H₂O, assay ≈ 99%), iron chloride (FeCl₃, assay ≈ 97%), and lithium sulfate (Li₂SO₄, assay ≥98.5% (titration)) were purchased from Sigma-Aldrich. Calcium sulfate dihydrate (CaSO₄·2H₂O, assay ≥ 98.0%), lithium bromide anhydrous (LiBr, assay ≥ 99.0%), ammonium sulfate ((NH₄)₂SO₄, assay ≥ 99.0%), and ethylenediaminetetraacetic acid (EDTA, assay ≥ 99.0%) were purchased from Samchun (South Korea). The glass fiber membrane was purchased from Whatman, Cytiva (USA). The activated carbon (surface area = 1900–2200 m²/g) was purchased from Power Carbon Technology (South Korea). The materials were used as received without further purification. Dulbecco’s modified Eagle medium (DMEM) with high glucose and sodium pyruvate was purchased from Gibco. Fetal bovine serum (FBS), penicillin/streptomycin, and cell counting kit-8 (CCK-8) were purchased from Merck (Germany), Lonza (Switzerland), and Dojindo (Japan), respectively.

Copper (II) chloride (CuCl₂.2H₂O, 99%, CAS number 10125-13-0, Alfa Aesar, Haverhill, MA, USA) and iron (II) chloride (FeCl₂.4H₂O, 98%, CAS number 13478-10-9, Alfa Aesar, Haverhill, MA, USA) were used for the synthesis of Cu-ferrite. Ethanol (200 Proof, CAS number 64-17-5) was purchased from Pharmco Aaper Products, Brookfield, CT, USA. Pluronic P123 surfactant (CAS number 9003-11-6) and propylene oxide (CH₃CHCH₂O, 99%, CAS number 75-56-9) were purchased from Sigma Aldrich, St. Louis, MO, USA. Idaho National Laboratory (INL) supplied the preprocessed corn stover feedstock (avg. size of 1.12 mm). For the activation of hydrochar, analytical-grade KOH (90%, CAS number 1310-58-3, Sigma Aldrich, St. Louis, MO, USA) and hydrochloric acid (HCl, 35.5%, CAS number 7647-01-0, Fisher-Scientific, Hampton, NH, USA) were used. Polytetrafluoroethylene (PTFE 60 wt.% dispersion in water, CAS number 9002-84-0, Sigma Aldrich, St. Louis, MO, USA), Super P conductive carbon black (CAS number 1333-86-4, MSE Supplies, Tucson, AZ, USA), and nickel foam substrates (1.6 mm thick, 99.9% purity, MTI Corporation, Richmond, CA, USA) were utilized for the preparation of working electrodes.

Indium tin oxide glasses (ITO, 7 Ω/sq) were obtained from Xin Yan Technology Limited. N, N-dimethylformamide (DMF) were supplied by Merck. AC, mesoporous carbon, polytetrafluoroethylene (PTFE), polyacrylonitrile (PAN, Mw = 150,000), silver wire (Ag, diam. 0.5 mm), 3, 4-ethylenedioxythiophene (EDOT, 97% purity), lithium perchlorate (LiClO₄, ≥97% purity) and manganese (II) sulfate monohydrate (MnSO₄•H₂O) were purchased from Sigma-Aldrich. KCl and sulphuric acid (H₂SO₄) were acquired from Fisher Scientific. Acetone and ethanol were supplied from HmbG Chemicals and J. Kollin Chemicals, respectively. Deionised water (18.2 MΩ.cm) was used throughout the experiments. All chemicals were directly used as obtained without further purification.

The as-synthesized
Na₂Fe₂F₇ materials were carbon-coated
prior to electrochemical testing to form an electronically conductive
carbon nanocomposite. The pristine materials were combined with carbon
black (Super C65, MTI Corporation) in a 7:2 ratio along with three
10 mm and three 5 mm ZrO₂ balls in a 50 mL ZrO₂ ball mill jar and ball-milled at 300 rpm for 24 h. The resultant
carbon-coated materials were hand-ground for 30 min with 10 wt % polytetrafluoroethylene
(Sigma-Aldrich), rolled into free-standing film electrodes, and punched
into 6 mm disks with a loading density of 10 mg cm^–2. All electrochemical testing occurred in Swagelok-type cells against
Na metal (Sigma) with a glass fiber separator (Whatman GF/D) using
200 μL of an in-house-prepared electrolyte (<20 ppm water
content) of 1 M NaPF₆ (Strem Chemicals, 99%) in propylene
carbonate (Sigma, 99.7%) with 2 vol % fluoroethylene carbonate (Sigma-Aldrich,
≥99%).