{
    "title": "Scalable fabrication of high-power graphene micro-supercapacitors for flexible and on-chip energy storage",
    "inventor_name": "Richard Kaner & Maher El-Kady",
    "publication_year": 2013,
    "device_name": "Graphene Micro-SuperCapacitor (LSG-MSC)",
    "goal": "Provide compact, high-power, flexible on-chip energy storage for miniaturized electronics.",
    "problem_addressed": "Conventional micro-fabrication of supercapacitors is costly and cumbersome, limiting widespread adoption of on-chip energy storage.",
    "concept_summary": "A LightScribe DVD burner laser directly writes inter-digitated graphene patterns onto graphite-oxide films, converting them to laser-sinter graphene (LSG). The resulting planar micro-supercapacitor is built on flexible PET, coated with a solid-state electrolyte (PVA-H_2SO_4 or ionogel), and can be fabricated in large numbers on a single disc in <30 min. The devices exhibit high volumetric power density (~200 uW cm^-^3), excellent cycling stability, and mechanical flexibility.",
    "detailed_description": "The process starts with a graphite-oxide (GO) dispersion coated on a PET sheet, which is adhered to a DVD disc. In a LightScribe optical drive, a computer-designed pattern is laser-etched; the laser thermally reduces GO to conductive graphene (LSG) at precise locations, forming inter-digitated electrode fingers (150 um spacing). Copper tape provides edge contacts and Kapton tape defines the active area. An electrolyte overcoat (either PVA-H_2SO_4 gel or an ionogel made from 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide and fumed silica) completes the planar micro-supercapacitor. Devices retain ~97 % capacitance after 1 000 bending cycles, lose only ~4 % after 10 000 charge-discharge cycles, and can power LEDs when connected in series/parallel configurations. The technique is scalable, allowing >100 devices per disc, and compatible with direct on-chip fabrication on CMOS/MEMS substrates.",
    "category": "Other",
    "principles": [
        "Laser-induced reduction of graphite oxide to graphene",
        "Inter-digitated electrode geometry for high surface area",
        "Electrochemical double-layer capacitance"
    ],
    "scientific_domains": [
        "Materials Science",
        "Electrical Engineering",
        "Chemistry"
    ],
    "mechanisms_of_action": [
        "Electrochemical double-layer charge storage",
        "Laser-driven conversion of GO to conductive graphene"
    ],
    "materials": [
        "Graphite oxide",
        "Graphene (laser-sinter)",
        "Polyethylene terephthalate (PET) substrate",
        "Copper tape",
        "Polyimide (Kapton) tape",
        "PVA-H_2SO_4 gel electrolyte",
        "Ionogel (ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide + fumed silica)"
    ],
    "energy_sources": [],
    "inputs": [
        "Electrical charge/discharge cycles",
        "Mechanical bending/twisting"
    ],
    "outputs": [
        "Stored electrical energy",
        "Power density ~200 uW cm^-^3",
        "Voltage ~0.35 V (self-charged variant)"
    ],
    "claimed_performance": "Volumetric power density ~200 uW cm^-^3; energy density three orders of magnitude higher than aluminium electrolytic capacitors; <4 % capacitance loss after 10 000 cycles; stable operation under bending.",
    "experimental_evidence": "Figures 1-7 in the Nature Communications article show fabrication steps, SEM images, IV curves, CV profiles at scan rates up to 10 000 mV s^-^1, galvanostatic charge/discharge at 1.68 x 10^4 mA cm^-^3, impedance spectra, and self-discharge comparisons with commercial supercapacitors.",
    "replication_status": "Demonstrated in the authors' laboratory; no independent third-party replication reported.",
    "keywords": [
        "graphene",
        "micro-supercapacitor",
        "laser reduction",
        "LightScribe",
        "flexible electronics",
        "on-chip energy storage",
        "inter-digitated electrodes"
    ],
    "related_technologies": [
        "Graphene supercapacitors",
        "Laser-induced graphene (LIG)",
        "Flexible solid-state electrolytes",
        "MEMS energy storage"
    ],
    "controversy_level": "low",
    "confidence_score": 0.9,
    "practicability_score": 0.8,
    "fringe_score": 0.1,
    "evidence_strength": 0.7,
    "risk_score": 0.1,
    "trl_estimate": 6,
    "source_urls": [
        "https://doi.org/10.1038/ncomms2446",
        "http://www.cornell.edu/",
        "http://ucla.edu"
    ],
    "organizations": [
        "University of California, Los Angeles (UCLA)",
        "California NanoSystems Institute"
    ],
    "applications": [
        "Flexible wearable electronics",
        "On-chip power for MEMS/CMOS",
        "Roll-up displays and e-paper",
        "Portable low-power devices"
    ],
    "limitations": [
        "Dependence on LightScribe DVD burner technology (phasing out)",
        "Electrolyte voltage window limits overall energy density",
        "Scale-up beyond disc size not demonstrated"
    ],
    "open_questions": [
        "How does long-term environmental exposure (humidity, temperature) affect device stability?",
        "Can higher-voltage electrolytes be integrated without compromising flexibility?",
        "What are the challenges for mass-production integration with standard CMOS fabs?"
    ],
    "red_flags": [],
    "evidence_quotes": [
        "These micro-supercapacitors demonstrate a power density of ~200 uW cm^-^3, which is among the highest values achieved for any supercapacitor.",
        "The LSG-MSC(16) shows excellent stability, losing only about 4 % of its initial capacitance over 10 000 cycles.",
        "More than 100 micro-supercapacitors can be produced on a single disc in 30 min or less.",
        "Bending/twisting the device has almost no effect on its performance.",
        "The devices can be directly fabricated on a chip that contains integrated circuits, which they can then power."
    ]
}