Documents / Official release
This Defense Intelligence Reference Document was prepared by the Defense Intelligence Agency's Defense Warning Office and dated 1 November 2010. It is one of a series of advanced technology reports produced under the Advanced Aerospace Weapons System Applications Program. The report reviews how ultracapacitors work, how they compare with batteries, their history and materials, and their commercial, military and aerospace uses. It concludes that new materials and cell designs will raise energy density and that the U.S. government must understand the devices' spectral signatures.
From the source: Release of 2026-09-18 Incident: 11/1/10, Las Vegas, Nevada. Released with redactions. This document is a Defense Intelligence Reference Document (DIRD), a technical reference format used by the Defense Intelligence Agency (DIA) to capture baseline knowledge on a specific topic for later analytic use. DIRDs are best understood as reference and synthesis products rather than as original research. It is one of 38 DIRDs produced under the Advanced Aerospace Weapon System Applications Program (AAWSAP) between 2009 and 2011. Because AAWSAP’s scope permitted a broad range of supporting topics, not every DIRD in the series directly concerns aerospace systems or future threat assessment. The following summary reflects the DIRD’s scope and framing at the time of writing and should not be read as implying current validation of the concepts discussed. This DIRD surveys ultracapacitors as high-power energy-storage devices and argues that their main value lies in extremely rapid charge and discharge, very long cycle life, and usefulness in systems that need short bursts of power rather than sustained energy delivery. The report explains how ultracapacitors differ from batteries, reviews the materials and cell designs that determine their performance, and emphasizes that they are especially useful for power stabilization, backup power, load leveling, regenerative braking, and other applications where fast energy transfer matters more than total stored energy. It also notes their drawbacks, including lower energy density, self-discharge, and voltage-management requirements that limit their usefulness as stand-alone replacements for batteries in many applications. The document presents ultracapacitors as a maturing and increasingly important technology whose most credible aerospace and military uses lie in pulsed-power, missile and munitions systems, electric propulsion support, and other hybrid power architectures rather than in long-duration primary energy storage.
UNCLASSIFIED11FOR. 8FFl@IAL tt.!! e"t I showing the electrochemical double layer responsible for the characteristic performance.5 The basic principles of operation have not changed with improved technologies, only the materials and cell design. The two electrode plates are traditionally the same material, which is usually a carbonaceous material, such as activated carbon. Each layer is capable of storing a low voltage, and multiple layers serve to increase the potential. Individual cells are placed in series to create a higher voltage, in much the same manner as a battery. Recent advances in ultracapacitors have moved toward employing dissimilar electrodes, which create a higher potential; since the electrodes are now different, these are sometimes referred to as "pseudo" or hybrid capacitors . The pseudocapacitor uses a battery-like electrode to replace one of the carbon electrodes, yielding a high-energy-storage electrode and a highly capacitive electrode within the same system. The capacitance of an ultracapacitor can be determined by the Helmholtz equation (equation 1), which describes the relationship between the electrolyte and the electrode: C = EA/d (1) Here, £ is the dielectric constant of the electrolyte, A is the available surface area, and d represents the distance between the center of the double layer and the electrode surface. Increasing the double-layer capacitance in an ultracap is generally accomplished by either manipulating the electrode (carbon) surface area or the electrolyte. Energy density (equation 2) is the product of the capacitance and the square of the voltage: E = ½ cv2 (2) Strategies for increasing the stored energy target improvements to both the electrodes and the electrolyte. Changing from an aqueous electrolyte to an organic electrolyte with a higher dielectric constant will increase the voltage from approximately 1 volt to more than 2.5 volts. Increasing the surface area of the electrode is another approach to increasing storage capability. There is a tradeoff between porosity and surface area that must be considered when constructing an electrode with an extremely high surface area. An activated carbon approaching a measured surface area of 3,000 m2/g may have less than half that as accessible or useable area. 6 Increasing the pore size sacrifices surface area but provides more accessible material. By providing more interfacial area between the electrode and the electrolyte, a better electrochemical double layer can be produced, yielding a better ultracapacitor. UNCLASSIFIEO/;LFOA OFFI&il:.l.b YS& OrtLY 2
Not linked to a story yet.
Official release, from the pursue collection. The PDF is mirrored here; the original link is above. 34 pages are in the text index: search them above, or from the library's search.