Sensors and Electron Devices Directorate Research Areas

Research on High-Energy Density and High Power Density Electrochemical Energy Storage Devices

Advisor: Jow, T. Richard (taiguang.jow@us.army.mil  301-394-0340)
Keywords: Electrochemistry; Lithium-ion-batteries; Electrodes; Electrolytes; Lithium mixed metal oxides; Electrochemical capacitors

High-power density lithium-ion (Li-ion) batteries and electrochemical capacitors with high energy density are increasingly needed in applications such as power tools, robotics, unmanned aerial vehicles (UAV), and hybrid electric vehicles (HEV). The state-of-the-art Li-ion batteries have encountered substantial reduction in power performance at temperatures below -30oC and reduced cycle and storage life at temperatures above 60oC. Furthermore, under shorting and overcharge conditions, the current Li-ion batteries will undergo thermal runaway and become dangerous. The energy density of the current Li-ion chemistries has reached their limits, 200 to 250 Wh/kg, while higher energy density Li-ion batteries are still desirable.
Research and development activities include investigation of factors limiting the low-temperature charge-transfer kinetics at the electrode/electrolyte interfaces, understanding solid-electrolyte interface (SEI) formation resulting from the electrolyte and electrode reactions for guiding materials development, synthesis and characterization of new solvents and salts for improved electrolytes and SEI properties, development of high voltage cathode for increased energy density, and development of compatible high voltage electrolytes.

References
Allen JL, Jow TR, Wolfenstine J: Chemistry of Materials 19: 2108, 2007
Xu K, et al: Journal of Physical Chemistry C 111: 7411, 2007