Historical research guide · 0336 · 2010

DIRD Ultracapacitors as Energy and Power Storage Devices for Commercial and Military Applications

DIA / AAWSAP contractor

In one minute

The Defense Intelligence Agency commissioned this review for its Advanced Aerospace Weapon System Applications programme and issued it on 1 November 2010. Ultracapacitors store charge physically, in the thin electrical double layer where an electrode meets its electrolyte, rather than through a chemical reaction — so there is no reaction to wear out, and a cell can be charged and discharged tens of millions of times. The report is clear about the trade that buys: think of a battery as storing watt-hours and an ultracapacitor as storing watts. A lithium cell carries 100 to 200 watt-hours per kilogram against about five, while the ultracapacitor returns five to ten kilowatts per kilogram and fills in about a second. The authors trace the technology from a 1966 Standard Oil patent to cranes, forklifts and hybrid buses, and say where it is going: aerospace pulsed power, electric propulsion and directed-energy weapons. The last chapters go further, to nanostructured carbons and a magnetic capacitor whose makers report a capacitance a billion times the electrostatic value.

Connection

Chapter 1 reads the AAWSAP reference set as one government stocktake of what an advanced craft would need, and this is the volume on holding and releasing power. Chapter 6 cares because every vacuum-energy or field-propulsion device eventually meets the same question — where the pulse comes from — and this report names both the storage physics and the material limit chapter 13 keeps arriving at.

From the source

An ultracapacitor stores charge physically in the electrical double layer rather than through a chemical reaction, so there is no direct degradation mechanism that limits cycle life; side reactions prevent a truly infinite count, but a cell can often be cycled tens of millions of times, against fewer than 5,000 cycles for a lithium ion battery at the 1C rate, and there is no limit on how deeply it may be discharged.Chapter 1, Batteries and Ultracaps, p. 3; Table 1, p. 4
The trade is power for energy, and the report puts it plainly: think of batteries as storing watt-hours and ultracaps as storing watts. A lithium ion cell holds 100 to 200 watt-hours per kilogram against about 5 for an ultracapacitor, while the ultracapacitor delivers 5 to 10 kilowatts per kilogram against 0.5 to 1, and charges or discharges in about a second where the battery needs three to five minutes.Table 1, p. 4; Figure 3, Ragone plot, p. 5
Capacitance follows the Helmholtz relation — dielectric constant times available area, divided by the double-layer gap — so the whole design problem is surface area and the ion. An activated carbon measuring 3,000 square metres per gram may offer less than half of that as usable area, and carbide-derived carbons tunable to within 0.05 nanometre showed that pores under one nanometre still store charge, because the ion’s solvation shell distorts and lets it approach the carbon surface more closely.Chapter 1, p. 2; Chapter 4, CNTs and Advanced Carbons, pp. 19-20; Figure 9
The report’s stated destination for the technology is military pulsed power: ultracapacitors already serve in munitions fusing and missile power load levelling, and extremely high power delivery makes them a potential vehicle for the power required by directed-energy weapons, with electric propulsion named alongside.Summary, p. iv; Chapter 3, Aerospace, pp. 15-16
Because they discharge so fast, ultracapacitors emit a distinctive broadband radio-frequency signature when they fire, which a modest wideband receiver may be able to detect, and the architecture of a given device may yield a signature unique to it; the report says this warrants further study, alongside the vulnerability of such devices to stimulated discharge.Chapter 3, Signatures and Vulnerabilities, p. 16
The boldest section is the magnetic capacitor: Northern Lights Semiconductor has been building thin-film cells in which the giant magneto-capacitance effect — normally seen far below 273 kelvin — works above 300 kelvin, with capacitance measured at 10^9 times that of an electrostatic capacitor and leakage and self-discharge essentially eliminated because the electrons are trapped in the magnetic field. At a wafer-scale production target the report projects specific energy exceeding lithium ion at significantly reduced cost.Chapter 4, Magnetic Capacitors, pp. 21-24; Figures 13-15

The way in

https://documents2.theblackvault.com/documents/dia/AAWSAP-DIRDs/DIRD_32-DIRD_Ultracapacitators_as_Energy_and_Power_Storage_Devices.pdf

Historical source-access record. This guide links to the original; it does not reproduce the paper text.

Defense Intelligence Reference Document, Defense Futures. DIA-08-1011-005, 01 November 2010 (IcOD: 20 July 2010). Produced in FY 2010 under the Defense Intelligence Agency Advanced Aerospace Weapons System Applications (AAWSA) Program. Released under FOIA and published by The Black Vault, where it is filed as DIRD 32. TITLE. The library record and the Black Vault filename carry the misspelling ‘Ultracapacitators’; the document’s own title page reads ‘Ultracapacitors as Energy and Power Storage Devices for Commercial and Military Applications’, and this sheet uses it. AUTHORS. The authors’ names are withheld under FOIA exemption (b)(6). The text describes carbon-nanotube forests grown at Lockheed Martin’s Advanced Technology Center, Lockheed Martin’s NEARLab fibre work, and Lockheed Martin’s nanomaterials and MRAM expertise as available capability — internal evidence that the contractor was Lockheed Martin, which is an inference and not an attribution. TEXT. Full text below, chapters 1 to 6. The document carries a copyright warning against further dissemination of its photographs, so the sixteen figures are not reproduced; their captions are kept. Table 2, the manufacturer comparison matrix, and chapter 7, the 48 endnotes, are omitted — both were reduced to unreliable fragments by the text extraction. Tables 1, 3 and 4 are rebuilt from the extracted values; one cell of Table 4 (aerogel carbon in KOH, volumetric capacitance) did not survive and is marked with a dash, and Table 1’s less-than and greater-than symbols are written out in words because the page is MDX. Equation 2 did not survive extraction; the sentence describing it is kept. The Helmholtz epsilon and the permittivity of free space were flattened to Latin letters by the extraction and are restored.

How to cite it

DIA / AAWSAP contractor (2010) DIRD Ultracapacitors as Energy and Power Storage Devices for Commercial and Military Applications https://documents2.theblackvault.com/documents/dia/AAWSAP-DIRDs/DIRD_32-DIRD_Ultracapacitators_as_Energy_and_Power_Storage_Devices.pdf

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