DOW-UAP-D147: Ultracapacitors as Energy and Power Storage Devices

Source file: DOW-UAP-D147_AAWSAP-DIRD-Ultracapacitors-as-Energy-and-Power-Storage-Devices-November-1-2010.pdf Originating agency: Defense Intelligence Agency (DIA), Defense Warning Office, under the AAWSA Program Document type: Defense Intelligence Reference Document (DIRD), "Defense Futures" series; control number DIA-08-1011-005 Date: 1 November 2010 (information cutoff date, ICOD: 20 July 2010) Classification: UNCLASSIFIED//FOR OFFICIAL USE ONLY, with the FOUO caveat struck through on every page; publicly released in 2026 Page count: 34 VIRIN: 260918-D-D0360-1136 PURSUE Release: 6

Summary

This DIRD is a technology primer on ultracapacitors, also called supercapacitors or electrochemical double-layer capacitors. The cover carries the DIA seal, the "Defense Futures" banner, the date 1 November 2010, an information cutoff date of 20 July 2010 and the control number DIA-08-1011-005. The title page says it was prepared by the Technology Warning Division (DWO-4) of the Defense Warning Office, Directorate for Analysis, names the authors only as "AAP Person 84, AAP Person 85," and describes the paper as "one of a series of advanced technology reports produced in FY 2010" under the AAWSA Program, with questions to be addressed to AAP Person 1, the AAWSA Program Manager.

The argument is simple and repeated throughout: ultracapacitors are power devices, not energy devices. They take or deliver a burst in about a second and can be cycled hundreds of thousands of times, but they store a small fraction of what a battery holds. The paper follows that trade-off through materials, markets and military uses, and gives its longest chapter to new electrode materials and to a start-up's "magnetic capacitor."

The paper does not mention UAP, UFOs or anomalous craft anywhere. Among the twelve technical areas of the AAWSAP Statement of Objectives (DOW-UAP-D110) it belongs most naturally to power generation, with side excursions into armament (directed-energy weapons) and signatures.

Research Article

Structure and sources

After a one-page summary, the body runs 29 numbered pages in seven chapters: Concept Overview (with sections on batteries versus ultracaps and on history), Materials Technology (electrolytes, electrodes), Applications (electronics and telecommunications, industrial, transportation, aerospace), Recent Developments (carbon nanotubes and advanced carbons, thin films, magnetic capacitors), Future Developments, Conclusions and Endnotes. There are 16 figures and 4 tables. The 47 endnotes lean on the Spring 2008 issue of the Electrochemical Society's Interface magazine, on manufacturer white papers (EPCOS, the Tecate Group) and on journal papers in Science, Nano Letters and Physical Review Letters; one figure is credited to Wikipedia Commons. A copyright warning forbids further dissemination of the photographs. Nothing in the paper reports measurements made by the authors, which matches the official description of DIRDs as synthesis rather than original research.

The physics: charge held in a double layer

A conventional capacitor stores energy by separating charge across a dielectric between two plates. An ultracapacitor stores it in the electrical double layer that forms where a porous carbon electrode meets a liquid electrolyte, "a vanishingly thin gap between two plates" (page 6). The paper gives the two governing equations: the Helmholtz relation C = εA/d, where A is the available surface area and d the thickness of the double layer, and E = ½CV² for stored energy (page 7). The two levers are therefore surface area and voltage. Activated carbon can reach a measured 3,000 m²/g, but "may have less than half that as accessible or useable area."

Because storage is physical rather than chemical, "there is no direct degradation mechanism that limits cycle life"; ultracaps "can often be cycled tens of millions of times" (page 8). Table 1 (page 9), explicitly "based upon 2008 data," frames the trade-off against a lithium-ion battery: charge and discharge in about 1 second versus 3-5 minutes; cycle life above 500,000 versus under 5,000; specific power of 5-10 kW/kg versus 0.5-1 kW/kg; but specific energy of only 5 Wh/kg versus 100-200 Wh/kg. Cost runs $10-20 per watt-hour against $1-2 for the battery, yet only $25-50 per kilowatt against $75-150. The paper's shorthand is to "think of batteries as storing watt-hours of energy and ultracaps as storing watts of power," and a Ragone plot (Figure 3) maps the two regimes. The drawbacks are stated plainly: self-discharge, a voltage that falls linearly as the device empties, and the resulting need for a power converter.

From SOHIO to seaport cranes: history and materials

The paper dates the modern device to 1966, when the Standard Oil Company of Ohio (SOHIO) patented it (Figure 4 reproduces the patent drawing); NEC sold the "SuperCapacitor" under licence from 1978, and Matsushita improved the electrodes in the 1980s. The first jobs were backup power for clock chips and CMOS memory. By 2010 cells ranged from millifarads to several kilofarads, a few specialised cells exceeded 100 kF, and the industry had "sales of several hundred million dollars per year" (page 11).

Chapter 2 traces three generations of electrolyte (Table 3, page 13). Aqueous electrolytes (potassium hydroxide, sulfuric acid, aluminium sulfate) conduct well but limit a cell to about 1.2 V. Organic solvents such as propylene carbonate and acetonitrile raised the rating to 2.3-2.7 V and up to 3 V. Ionic liquids reach 4 V at the cost of high resistivity, 125 ohm-cm at 25°C. A small internal inconsistency: page 7 attributes the higher organic voltage to a "higher dielectric constant," while page 13 gives the more accurate reason, a "higher breakdown potential."

Table 2 (page 12) compares 18 commercial devices from eleven makers, among them Maxwell, Ness, EPCOS, Panasonic, BatScap and JSR Micro, rated at 2.5-3.8 V with specific energies from 2.3 to 12.1 Wh/kg; the best figures come from hybrid designs. That is where the paper sees the next step: "pseudocapacitors" that replace one carbon electrode with a battery-like metal oxide or conductive polymer. Ruthenium oxide reaches 1,300 F/cm³ against 110-125 F/cm³ for carbon in an aqueous electrolyte (page 16), though supply and cost push researchers toward manganese and nickel oxides. The paper expects such designs to manage "tens of thousands of cycles," and near-term engineering to lift commercial cells from 4 to 5-6 Wh/kg (page 17).

Applications, and a short intelligence section

Chapter 3 moves from camera flashes (nearly one billion camera phones were sold in 2009) and GSM, GPRS and WiMAX data cards, where transmission peaks exceed what USB can supply, to forklifts, cranes, elevators and grid levelling for wind farms. Figure 6 shows a fuel-cell forklift in which the ultracapacitor absorbs energy as the load descends and returns it for the next lift. In transport, the paper notes that "Earliest uses of ultracapacitors were in motor startup for tanks and submarines" and that military adoption lowered costs enough for trucks and locomotives; in an ultracap/battery hybrid, regenerative braking can recover "as much as 38% of the propulsion energy" (page 19). The aerospace section lists failsafe vehicle electronics, fire control, airbags, the bridge power used while an aircraft switches from ground to onboard supply, cold-engine starts, GPS-guided missiles and projectiles, naval pulsed power and directed-energy weapons.

The one passage written from an intelligence point of view is a half-page headed "Signatures and Vulnerabilities" (page 20). Its opening sentence, highlighted in yellow in the released copy, says ultracapacitors "could be important in the development of ultrawideband energy weapons," a niche the paper says was previously dominated by bulk acoustic semiconductor switch (BASS) devices. It argues that a fast discharge will emit "a distinctive broadband RF signature" detectable by "a modest wideband receiver," that the signature might reveal the type of device, and that idle ultracaps might betray themselves through their large electrostatic potentials. A follow-on paragraph ("Stimulated Discharge," page 21) lists research topics such as circuit vulnerability analysis and "laboratory stimulated discharge experiments." No data or cases support these points; they are framed as warranting further study.

New carbons and the "magnetic capacitor"

Chapter 4 surveys the materials frontier. Vertically aligned carbon-nanotube "forests" first gave disappointing capacitance, blamed on hydrophobic tube walls and addressed by surface functionalization. The paper illustrates them with a forest grown at Lockheed Martin's Advanced Technology Center (LMATC, Figure 7) and mentions CNT-coated glass fibres from Lockheed Martin's NEARLab as possible structural energy storage. Graphene's theoretical figures are given as 2,600 m²/g surface area, 5,000 W/m·K thermal conductivity and 200,000 cm²/V·s carrier mobility, against measured capacitances of 135-205 F/g (page 23). Carbide-derived carbons, made by stripping metal from carbides with chlorine at 500-1,000°C, allow pore sizes tuned with "sub-angstrom accuracy"; work credited to Drexel University found that pores below 1 nm raise capacitance even though the solvated ions are larger than the pores, explained by a "distorted ion shell model" (page 24). Because chlorination can run at 200°C, carbide-derived films could be grown on the same chip as the circuits they power (Figure 10). The text states the film thickness range as "200 to ~2 mm," but Figure 11's axis is in micrometres, an apparent slip.

The most striking claims concern the MCap of Northern Lights Semiconductor Corp. (NLSC), in development since 2007. It relies on giant magnetocapacitance (GMC), which the paper calls "a quantum mechanical effect" seen in stacks of alternating ferromagnetic and nonmagnetic films, normally only well below 273 K. NLSC's nanocells, each about 1.6 by 0.55 micrometres (Figure 12), are said to show GMC above 300 K, and the paper states that GMC has produced a capacitance "measured to be 10⁹ times larger than that observed in electrostatic capacitors," with leakage and self-discharge "essentially eliminated" (page 27). Figures 13-15 show test curves (one set attributed to Taiyo Yuden), the growth in working nanocells through 2009, and NLSC's own projection that a production GMC factor of about 10⁹ would beat lithium-ion specific energy at far lower cost and "disrupt both the lithium ion battery and the ultracapacitor market" (page 29).

This section needs to be read with care. It rests on the developer's reported data. The endnotes cite peer-reviewed work on giant magnetocapacitance in general (rare-earth manganites, DyMn2O5, doped SnO2 films), but no publication describing the MCap device itself. The tone is promotional: the paper adds that "Coupled with Lockheed Martin's extensive nanomaterials and device physics experience, it is likely that NLSC will be able to use its MRAM development expertise to accomplish this." A billion-fold capacitance gain in a practical device would be an extraordinary result, and the section does not discuss the voltage such cells can withstand, which matters as much as capacitance for stored energy.

Forecast to 2030 and beyond

Chapter 5 sets out a timeline. For 2010-2020 it expects better electrodes, electrolytes and packaging, a shift to asymmetric designs, and predicts that "Both thin-film and MCap devices will become prevalent"; if MCaps reach lithium-ion specific energy, adoption will be "rapid and revolutionary." For 2020-2030 it expects advanced carbons, hybrid cells, a replacement for ruthenium oxide, ionic-liquid electrolytes and three-dimensional electrodes built into chips. Beyond 2030 it declines to be precise, then predicts that "nearly all microelectronic circuitry will incorporate thin-film ultracaps or MCaps, and laptop computers will become the size of an iPhone with mostly voice-activated functions" (page 31). Figure 16 illustrates the shrinkage with pictures for 2010, 2020, 2030 and 2050. The conclusions (page 32) add that better carbon electrodes alone "could double the energy density" and close with a policy note: the government must understand "the unique spectral signatures these devices generate."

Significance

D147 is a competent 2010 snapshot of a mainstream technology, not an exotic one. Its connection to AAWSAP runs through power: a future aerospace platform, a directed-energy weapon or an electric thruster needs to store and release large bursts of power, and the paper names "pulsed power storage and delivery for electric propulsion and directed-energy weapons" as the ultimate application (page 5). Its "Defense Futures" warning outlook shows in the half-page on RF signatures and in the closing call for the U.S. government to track the technology. It says nothing about UAP and draws no link to unexplained phenomena. The main caveats are its 2008 comparison data (which the authors acknowledge), its forecasts, and the reliance of its most dramatic section on one company's claims, presented alongside favourable references to Lockheed Martin laboratories. Read beside the release's DIRDs on warp drives and wormholes (DOW-UAP-D138, DOW-UAP-D139), it shows how wide AAWSAP's reference library was, from speculative physics to engineering that was already on the market.

Key People

Locations

Key Concepts

Notable Quotes

"Ultimately, application will be pulsed power storage and delivery for electric propulsion and directed-energy weapons." -- page 5

"To better understand the differences between batteries and ultracaps, it helps to think of batteries as storing watt-hours of energy and ultracaps as storing watts of power." -- page 9

"Earliest uses of ultracapacitors were in motor startup for tanks and submarines." -- page 19

"Because ultracapacitors have very high discharge rates, they will emit a distinctive broadband RF signature when discharged. A modest wideband receiver may be able to detect this discharge; its proximity will depend upon the construction of the target device." -- page 20

"When searching for ultracaps in the field that are not in use, the large electrostatic potentials may provide a clue." -- page 20

"Based on quantum theory, GMC brings about a capacitance which, to date, has been measured to be 10⁹ times larger than that observed in electrostatic capacitors." -- page 27

"It can be expected, however, that nearly all microelectronic circuitry will incorporate thin-film ultracaps or MCaps, and laptop computers will become the size of an iPhone with mostly voice-activated functions." -- page 31

"Their specific performance capabilities must be optimally utilized and we must have a keen understanding and awareness of the unique spectral signatures these devices generate when storing high power and in charge or discharge modes." -- page 32