{
    "title": "Cotton Carbon Supercapacitor",
    "inventor_name": "Xiaodong Li",
    "publication_year": 2012,
    "device_name": "Cotton Supercapacitor",
    "goal": "Provide a flexible, low-cost, environmentally friendly energy-storage device for wearable electronics, roll-up displays, and implanted medical implants.",
    "problem_addressed": "Current energy-storage solutions are rigid, expensive, and often derived from non-renewable carbon sources; a need exists for flexible, cheap, and green supercapacitors.",
    "concept_summary": "A $5 cotton T-shirt is chemically activated by soaking in sodium fluoride and sequential heating to convert the fibers into activated carbon while retaining flexibility. The resulting carbon textile is then coated with a nano-layer of manganese oxide (MnO_2) to form a flexible supercapacitor that exhibits 97.3 % capacitance retention after 1 000 charge-discharge cycles.",
    "detailed_description": null,
    "category": "Materials Science & Ceramics",
    "principles": [
        "Electrical double-layer capacitance",
        "Pseudocapacitance from MnO_2",
        "Chemical activation of cellulose to porous carbon"
    ],
    "scientific_domains": [
        "Materials Science",
        "Electrochemistry",
        "Energy Storage"
    ],
    "mechanisms_of_action": [
        "Sodium fluoride-mediated chemical activation of cotton fibers to form porous activated carbon",
        "Thermal treatment to carbonize and increase conductivity",
        "Deposition of a MnO_2 nano-layer providing pseudocapacitive redox activity",
        "Charge storage via electrical double-layer formation in the carbon pores and Faradaic reactions of MnO_2"
    ],
    "materials": [
        "Cotton (cellulose fibers)",
        "Sodium fluoride (NaF)",
        "Activated carbon (derived from cotton)",
        "Manganese oxide (MnO_2) nano-layer"
    ],
    "energy_sources": [],
    "inputs": [
        "Electrical charging voltage",
        "Mechanical flexibility (folding, bending)"
    ],
    "outputs": [
        "Discharged electrical energy to power devices",
        "Minor heat during charge/discharge"
    ],
    "claimed_performance": "97.3 % capacitance retention after 1 000 cycles; performance comparable to other carbon-based supercapacitors; cost up to 10x lower than coal- or petroleum-derived activated carbon.",
    "experimental_evidence": "Prototype tested for 1 000 charge-discharge cycles with 97.3 % retention; electrochemical characterization (CV) reported in Advanced Materials abstract shows superior performance of MnO_2-coated carbon textile.",
    "replication_status": "Prototype demonstrated; scaling up and independent replication not yet reported.",
    "keywords": [
        "Cotton",
        "Activated carbon",
        "MnO_2",
        "Supercapacitor",
        "Flexible energy storage",
        "Wearable electronics",
        "Green manufacturing"
    ],
    "related_technologies": [
        "Flexible electronics",
        "Wearable chargers",
        "Implanted medical power sources",
        "Roll-up displays"
    ],
    "controversy_level": "low",
    "confidence_score": 0.9,
    "practicability_score": 0.8,
    "fringe_score": 0.1,
    "evidence_strength": 0.6,
    "risk_score": 0.1,
    "trl_estimate": 5,
    "source_urls": [
        "http://www.ideaconnection.com/new-inventions/cotton-super-capacitors-05914.html",
        "http://news.discovery.com/tech/cotton-t-shirt-battery-120525.html",
        "http://onlinelibrary.wiley.com/doi/10.1002/adma.201200246/abstract"
    ],
    "organizations": [
        "University of South Carolina"
    ],
    "applications": [
        "Flexible electronics",
        "Roll-up displays",
        "Implanted medical devices",
        "Wearable power chargers"
    ],
    "limitations": [
        "Scalability of the activation and coating process not yet demonstrated",
        "Performance comparable but not markedly superior to existing supercapacitors",
        "Long-term mechanical durability under repeated flexing unknown"
    ],
    "open_questions": [
        "How does the device perform beyond 1 000 cycles?",
        "What is the capacitance retention under repeated bending and stretching?",
        "Can the process be scaled economically for mass production?"
    ],
    "red_flags": [],
    "evidence_quotes": [
        "\"After 1,000 cycles it had 97.3 percent retention.\"",
        "\"The still-flexible material was then coated with a nano-layer of metal manganese oxide, transforming the fabric to a super capacitor with 97.3 percent retention.\"",
        "\"The process is inexpensive and eco-friendly, costing up to 10 times less than processing coal or petroleum into activated carbon.\"",
        "\"Their device's performance is on par with other carbon-based super capacitors, according to their testing.\"",
        "\"A simple low-cost process, and it's green,\" Li said."
    ]
}