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As troops find themselves carrying a growing array of sophisticated battery-powered devices, US Army researchers are investigating new portable power technologies that can safely supply adequate amounts of energy for longer periods of time for soldiers who must operate in a challenging military environment.

Ashley Ruth, a chemical engineer in the Army Communications-Electronics Research, Development and Engineering Center (CERDEC), notes that current Army battery research is focusing on two specific models. “We are looking at improving primary–single use–and rechargeable battery technology,” she says. “Primary batteries have the benefit of higher energy density, which equates to a longer runtime.”  

Chemistries being studied include lithium-sulfur (Li-S) and lithium-air (Li-Air), both of which have the promise of doubling energy density or runtime.

According to c4isrnet.com, researchers in CERDEC are also investigating a more reliable rechargeable chemistry, a high-voltage, manganese-based system that promises to yield a 25 percent energy density increase. “In our lab we have demonstrated success by modifying the structure with chlorine and transition metal dopants,” Ruth said. The dopants stabilize the battery, allowing significantly deeper discharges resulting in greater power capacity. “Due to the material stability, we determined a four-fold power increase would be achievable,” Ruth said.

Already in the Army’s portable power pipeline is the Conformal Wearable Battery (CWB). First announced in 2013, the lithium-ion (Li-ion)-based CWB is a thin, lightweight, flexible battery that’s designed to integrate seamlessly into a soldier’s body armor to provide centralized power to multiple C4ISR devices.

“It conforms to the body and can be worn in either the side, chest or back pouches with the ballistic protective plates, virtually invisible and transparent to the soldier,” said Deanna Tyler, system engineering lead at CERDEC CP&I.

The CWB was developed to serve as a centralized power source for the Army’s Nett Warrior, a smart phone-based, integrated, dismounted leader situational awareness system designed for tactical operations. A major CWB drawback is its inability to be recharged while its user is on the move.

Working on the cutting edge of battery technology, researchers at the Army Research Laboratory (ARL) and the University of Maryland (UMD) have developed an innovative “water-in-salt” aqueous lithium-ion battery that promises to supply power, efficiency and longevity comparable to today’s lithium-ion batteries, yet without the current fire and chemical risks. The research could lead to a new generation of safer and possibly less expensive Li-ion batteries. The new battery features a water-based electrolyte containing ultrahigh concentrations of a specially selected lithium salt.