Information Net for August 20

Army MARS expands HQ

Read by: RANDY KJ4TFU

Fort Huachuca, AZ—Army MARS headquarters operations will be expanded with recruiting of a fulltime senior MARS Program Officer, it was disclosed Friday (Aug. 10) by Stephen G. Klinefelter, Chief of the Army Military Auxiliary Radio Service.

The Program Officer position is the first fulltime staff expansion at MARS headquarters in at least a decade. “This is a significant change of affairs,’ Klinefelter said. “We are going to strengthen processes and communications to meet our future challenges.”

In another sign of the auxiliary’s response to growing need for its services, the 10 volunteer Region Directors are being summoned to a three-day planning conference with headquarters staff at Dallas Sept. 11-13.

Defense Department spending on its three ham radio auxiliaries (Army, Air Force and Navy-Marine Corps) had been steadily cut back in recent years as more and more communications switched from HF to satellite and combat operations in the Middle East drained available funds. Army MARS formerly operated three area gateway stations in the continental U.S. all with fulltime administrators and military operators. Only one remains, here at Ft Huachuca, operated by civilian contract employees. The Chief’s job had been fulltime until 2007.

Read by: JERRY KE4ETY

Lately, however, MARS, with trained communicators distributed throughout the U.S., has been gaining increased attention as defense planners focused on the terrorist threat to conventional communications infrastructure.

The new MARS Program Officer will serve as a full-time aide to Klinefelter, who added the part-time Chief’s responsibilities to his primary job as an operations officer at the Network Enterprise Technology Command (NETCOM) earlier this year. A retired colonel with 31 years in uniform, Klinefelter will retain the latter position in G-3 (Operations). NETCOM headquarters here oversees the army’s computer and communications systems worldwide.

He said the new Civil Service position, which is being advertised on the official USAJOBS.GOV site today, will be filled as quickly as possible. A search for candidates has been underway while final approval of the new position was pending.

The job calls for a civilian with recent senior-level Army and staff experience (civilian or military) plus applicable advanced degree and both General Commercial and Amateur Extra FCC radio licenses. The pay starts at $84,000 not including federal locality allowance.
– Bill Sexton N1IN Army MARS HQ PAO

Lithium-ion Battery

Read by: MARTHA KJ4RIQ

A lithium-ion battery (sometimes Li-ion battery or LIB) is a family of rechargeable batterytypes in which lithiumions move from the negative electrodeto the positive electrode during discharge, and back when charging. Li-ion batteries use an intercalatedlithium compound as the electrode material, compared to the metallic lithium used in the non-rechargeablelithium battery.

Lithium-ion batteries are common in consumer electronics. They are one of the most popular types of rechargeable battery for portable electronics, with one of the best energy densities, no memory effect, and only a slow loss of chargewhen not in use. Beyond consumer electronics, LIBs are also growing in popularity for military, electric vehicle, and aerospace applications. Research is yielding a stream of improvements to traditional LIB technology, focusing on energy density, durability, cost, and intrinsic safety.

Chemistry, performance, cost, and safety characteristics vary across LIB types. Handheld electronics mostly use LIBs based on lithium cobalt oxide(LCO), which offers high energy density, but have well-known safety concerns, especially when damaged. Lithium iron phosphate(LFP), lithium manganese oxide(LMO) and lithium nickel manganese cobalt oxide(NMC) offer lower energy density, but longer lives and inherent safety. These chemistries are being widely used for electric tools, medical equipment and other roles. NMC in particular is a leading contender for automotive applications. Lithium nickel cobalt aluminum oxide(NCA) and lithium titanate(LTO) are specialty designs aimed at particular niche roles.

Charge and discharge

Read by: NICKI KF4DHK

During discharge, lithium ions Li+ carry the currentfrom the negative to the positive electrode, through the non-aqueous electrolyte and separator diaphragm.

During charging, an external electrical power source (the charging circuit) applies an over-voltage (a higher voltage but of the same polarity) than that produced by the battery, forcing the current to pass in the reverse direction. The lithium ions then migrate from the positive to the negative electrode, where they become embedded in the porous electrode material in a process known as intercalation.

History

Read by: RICK N9GRW

Lithium batteries were first proposed by M. S. Whittingham, now at Binghamton University, while working for Exxonin the 1970s. Whittingham used titanium(II) sulfide and lithium metal as the electrodes.

The reversible intercalation in graphite and intercalation into cathodic oxides was also discovered in the 1970s by J. O. Besenhard at TU Munich. Anmol also proposed the application as high energy density lithium cells. Electrolyte decomposition and solvent co-intercalation into graphite were severe drawbacks for long battery cycle life.

Primary lithium batteries in which the negative electrode is made from metallic lithium pose safety issues. As a result, lithium-ion batteries were developed in which both electrodes are made of a material containing lithium ions.

Read by: PAUL KJ4WQN

In 1979, John Goodenough demonstrated a rechargeable cell with high cell voltage in the 4V range using lithium cobalt oxide(LiCoO2) as the positive electrode and lithium metal as the negative electrode. This innovation provided the positive electrode material which made LIBs possible. LiCoO2 is a stable positive electrode material which acts as a donor of lithium ions, which means that it can be used with a negative electrode material other than lithium metal. By enabling the use of stable and easy-to-handle negative electrode materials, LiCoO2 opened a whole new range of possibilities for novel rechargeable battery systems.

In 1977, Samar Basu demonstrated electrochemical intercalation of lithium in graphite at the University of Pennsylvania. This led to the development of a workable lithium intercalated graphite electrode at Bell Labs(LiC6) to provide an alternative to the lithium metal electrode battery.

In 1980, Rachid Yazami also demonstrated the reversible electrochemical intercalation of lithium in graphite. The organic electrolytes available at the time would decompose during charging if used with a graphite negative electrode, preventing the early development of a rechargeable battery which employed the lithium/graphite system. Yazami used a solid electrolyte to demonstrate that lithium could be reversibly intercalated in graphite through an electrochemical mechanism. The graphite electrode discovered by Yazami is currently the most commonly used electrode in commercial lithium ion batteries.

In 1983, Dr. Michael Thackeray, Goodenough, and coworkers identified manganese spinel as a cathode material. Spinel showed great promise, given its low-cost, good electronic and lithium ion conductivity, and three-dimensional structure, which gives it good structural stability. Although pure manganese spinel fades with cycling, this can be overcome with chemical modification of the material.[28] Manganese spinel is currently used in commercial cells.

In 1985, Akira Yoshino assembled a prototype cell using carbonaceous material into which lithium ions could be inserted as one electrode, and lithium cobalt oxide (LiCoO2), which is stable in air, as the other. By using materials without metallic lithium, safety was dramatically improved over batteries which used lithium metal. The use of lithium cobalt oxide (LiCoO2) enabled industrial-scale production to be achieved easily.

This was the birth of the current lithium-ion battery.

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