Synthesis · Manganese oxide and urea-assisted engineering of nickel-iron compounds for high-performance battery-supercapacitor hybrid devices

8 structured synthesis routes

Completeness describes how fully the route could be reconstructed from the main article and supporting information.

Partial recipeSource: Main

Route 1: Other

2 · 2.3

Metal precursorsNiFe-Mn3 positive electrode

Solvents3 M KOH electrolyte

AdditivesrGO negative electrode

Atmospherenot reported

Substrate orientationNi foam-supported positive and negative electrodes

Work-updevice assembly details beyond electrode/electrolyte selection not reported

Activationnot reported

Scalability contextDevice fabrication details are sparse; electrode mass balancing and separator are not stated in text layer.

Show 3 structured reagent records

Role	Reagent	Amount / concentration	Source
Other	NiFe-Mn3 positive electrode	not reported	2 · 2.3
Other	rGO negative electrode	not reported	2 · 2.3
Electrolyte	KOH	not reported · 3 M	2 · 2.3

Complete recipeSource: Main

Route 2: Hydrothermal

2 · 2.1

Metal precursors0.35 g Ni(NO3)2 . 6 H2O; 0.48 g Fe(NO3)3 . 9 H2O

Linker precursors0.168 g terephthalic acid

Solvents2.5 mL ethanol; 20 mL dimethylformamide; 2.5 mL deionised water

Atmospherenot reported

Temperature150

Time6

Substrate orientationclean Ni foam, 3 x 1 cm2, placed in Teflon liner

Oxidant / reductantnitrate metal salts

Work-upCooled to room temperature; electrode removed and washed several times with DIW.

ActivationDried in vacuum oven at 60 deg C overnight.

Scalability contextAuthors note urea is inexpensive and environmentally friendly for scaling energy-storage materials, but no scale-up synthesis was demonstrated for NiFe.

Show 7 structured reagent records

Role	Reagent	Amount / concentration	Source
Linker	terephthalic acid (Showa, 99.0%)	0.168 g	2 · 2.1
Metal Source	Ni(NO3)2 . 6 H2O (Thermos Scientific, 99%)	0.35 g	2 · 2.1
Metal Source	Fe(NO3)3 . 9 H2O (Showa, 99%)	0.48 g	2 · 2.1
Solvent	ethanol (Echo, 95%)	2.5 mL	2 · 2.1
Solvent	dimethylformamide (Macron, 99.8%)	20 mL	2 · 2.1
Solvent	deionized water	2.5 mL	2 · 2.1
Other	clean Ni foam	3 x 1 cm2	2 · 2.1

Complete recipeSource: Main

Route 3: Hydrothermal

2 · 2.2 · Table 1

Metal precursors2 mmol MnCl2 . 4 H2O; NiFe precursor electrode supplies Ni/Fe framework

Linker precursorsNiFe-MOF linker inherited from pre-synthesised NiFe precursor

Solvents40 mL ethanol

Additives0.75 mmol urea

Atmospherenot reported

Temperature120

Time12

Substrate orientationpiece of clean NiFe electrode in Teflon liner

Oxidant / reductantnot reported

Work-upCooled to room temperature; electrode removed and washed several times with DIW.

ActivationDried in vacuum oven at 60 deg C overnight.

Scalability contextUrea described as inexpensive, non-toxic and attractive for scale-up, but no scaled synthesis was shown.

Show 4 structured reagent records

Role	Reagent	Amount / concentration	Source
Metal Source	manganese chloride tetrahydrate (MnCl2 . 4 H2O, Acros, 99+%)	2 mmol	2 · 2.2 · Table 1
Additive	urea (Showa, 98.0%)	0.75 mmol	2 · 2.2 · Table 1
Solvent	ethanol	40 mL	2 · 2.2 · Table 1
Other	clean NiFe electrode	one piece	2 · 2.2 · Table 1

Complete recipeSource: Main

Route 4: Hydrothermal

2 · 2.2 · Table 1

Metal precursors4 mmol MnCl2 . 4 H2O; NiFe precursor electrode supplies Ni/Fe framework

Linker precursorsNiFe-MOF linker inherited from pre-synthesised NiFe precursor

Solvents40 mL ethanol

Additives1.50 mmol urea

Atmospherenot reported

Temperature120

Time12

Substrate orientationpiece of clean NiFe electrode in Teflon liner

Oxidant / reductantnot reported

Work-upCooled to room temperature; electrode removed and washed several times with DIW.

ActivationDried in vacuum oven at 60 deg C overnight.

Scalability contextUrea described as inexpensive, non-toxic and attractive for scale-up, but no scaled synthesis was shown.

Show 4 structured reagent records

Role	Reagent	Amount / concentration	Source
Metal Source	manganese chloride tetrahydrate (MnCl2 . 4 H2O, Acros, 99+%)	4 mmol	2 · 2.2 · Table 1
Additive	urea (Showa, 98.0%)	1.50 mmol	2 · 2.2 · Table 1
Solvent	ethanol	40 mL	2 · 2.2 · Table 1
Other	clean NiFe electrode	one piece	2 · 2.2 · Table 1

Complete recipeSource: Main

Route 5: Hydrothermal

2 · 2.2 · Table 1

Metal precursors8 mmol MnCl2 . 4 H2O; NiFe precursor electrode supplies Ni/Fe framework

Linker precursorsNiFe-MOF linker inherited from pre-synthesised NiFe precursor

Solvents40 mL ethanol

Additives3.00 mmol urea

Atmospherenot reported

Temperature120

Time12

Substrate orientationpiece of clean NiFe electrode in Teflon liner

Oxidant / reductantnot reported

Work-upCooled to room temperature; electrode removed and washed several times with DIW.

ActivationDried in vacuum oven at 60 deg C overnight.

Scalability contextUrea described as inexpensive, non-toxic and attractive for scale-up, but no scaled synthesis was shown.

Show 4 structured reagent records

Role	Reagent	Amount / concentration	Source
Metal Source	manganese chloride tetrahydrate (MnCl2 . 4 H2O, Acros, 99+%)	8 mmol	2 · 2.2 · Table 1
Additive	urea (Showa, 98.0%)	3.00 mmol	2 · 2.2 · Table 1
Solvent	ethanol	40 mL	2 · 2.2 · Table 1
Other	clean NiFe electrode	one piece	2 · 2.2 · Table 1

Partial recipeSource: Both

Route 6: Hydrothermal

4 · 3.1 · Figure S1

Metal precursorsInferred same MnCl2 . 4 H2O amount as NiFe-Mn3 (8 mmol), but SI table values not exposed

Linker precursorsNiFe-MOF linker inherited from NiFe precursor

Solventsethanol, inferred 40 mL from same conditions as NiFe-Mn3

Additivesurea omitted

Atmospherenot reported

Temperature120 (inferred same as NiFe-Mn3)

Time12 (inferred same as NiFe-Mn3)

Substrate orientationNiFe precursor electrode in Teflon liner; exact details not exposed in SI text

Oxidant / reductantnot reported

Work-upnot independently reported for no-urea control; likely same as NiFe-Mn route

Activationnot independently reported for no-urea control; likely same as NiFe-Mn route

Show 3 structured reagent records

Role	Reagent	Amount / concentration	Source
Metal Source	MnCl2 . 4 H2O	8 mmol inferred	4 · 3.1 · Figure S1
Solvent	ethanol	40 mL inferred	4 · 3.1 · Figure S1
Other	NiFe electrode	one piece inferred	4 · 3.1 · Figure S1

Complete recipeSource: Main

Route 7: Hydrothermal

2 · 2.2 · Table 1

Metal precursors16 mmol MnCl2 . 4 H2O; NiFe precursor electrode supplies Ni/Fe framework

Linker precursorsNiFe-MOF linker inherited from pre-synthesised NiFe precursor

Solvents40 mL ethanol

Additives6.00 mmol urea

Atmospherenot reported

Temperature120

Time12

Substrate orientationpiece of clean NiFe electrode in Teflon liner

Oxidant / reductantnot reported

Work-upCooled to room temperature; electrode removed and washed several times with DIW.

ActivationDried in vacuum oven at 60 deg C overnight.

Scalability contextUrea described as inexpensive, non-toxic and attractive for scale-up, but no scaled synthesis was shown.

Show 4 structured reagent records

Role	Reagent	Amount / concentration	Source
Metal Source	manganese chloride tetrahydrate (MnCl2 . 4 H2O, Acros, 99+%)	16 mmol	2 · 2.2 · Table 1
Additive	urea (Showa, 98.0%)	6.00 mmol	2 · 2.2 · Table 1
Solvent	ethanol	40 mL	2 · 2.2 · Table 1
Other	clean NiFe electrode	one piece	2 · 2.2 · Table 1

Vague recipeSource: Main

Route 8: Drop Cast

2-3 · 2.3

Solventsnot reported

Additivescommercial rGO paste, EscortRam Ultraphene EX, 10-20 um

Atmospherenot reported

Substrate orientationNi foam

Work-upnot reported

Activationnot reported

Scalability contextUses commercial rGO paste; deposition loading and drying conditions not reported.

Show 2 structured reagent records

Role	Reagent	Amount / concentration	Source
Other	commercial rGO paste (EscortRam Ultraphene EX)	not reported · 10-20 um	2-3 · 2.3
Other	Ni foam	not reported	2-3 · 2.3