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An electrochemical quartz crystal microbalance is used in an investigation of the corrosion of aluminum in electrolytes appropriate for lithium batteries. The electrolytes are solutions of LiN ( CF 3 SO 2 ) 2 , LiC ( CF 3 SO 2 ) 3 , LiCF 3 SO 3 , LiPF 6 , LiBF 4 , and LiClO 4 , singly or in a limited number of combinations, in propylene carbonate (PC) and polyethylene glycol dimethyl ether. Aluminum that is scratched or abraded in an inert atmosphere (so that a protective surface film does not reform) undergoes significant corrosion in PC containing LiN ( CF 3 SO 2 ) 2 , LiC ( CF 3 SO 2 ) 3 , LiCF 3 SO 3 , and LiClO 4 , but forms a protective film in PC containing LiPF 6 , or LiBF 4 . A mechanism of corrosion of aluminum in LiN ( CF 3 SO 2 ) 2 / PC is proposed. © 2000 The Electrochemical Society. All rights reserved.

A thermal analysis of lithium‐ion batteries during charge/discharge and thermal runaway has been carried out with a mathematical model. The main concern with the thermal behavior of the room temperature batteries is the possible significant temperature increase which may cause thermal runaway. The emphases of this work include the examination of the effects of battery design parameters and operating conditions on temperature rise/profile during normal battery operation and the evaluation of the possibility of the occurrence of thermal runaway due to battery abuse.

Flexibility, lightness and printability make organic solar cells (OSC) strong candidates to power low consumption devices such as envisioned for the Internet of Things. Such devices may be placed indoors, where light levels are well below typical outdoors level. Here, we demonstrate that maximizing the efficiency of OSC for indoor operation requires specific device optimization. In particular, minimizing the dark current of the solar cells is critical to enhance their efficiency under indoor light. Cells optimized for sunlight reach 6.2 % power conversion efficiency (PCE). However when measured under simulated indoor light conditions, the PCE is to 5.2 %. Cells optimized for indoor operation yield 7.6 % of PCE under indoor conditions. As a proof-of-concept, the solar cells are combined with fully printed super-capacitors to form a photo-rechargeable system. Such a system with a 0.475 cm 2 indoor-optimized solar cell achieved a total energy conversion and storage efficiency (ECSE) of 1.57 % under 1-sun, providing 26 mJ of energy and 4.1 mW of maximum power. Under

Mathematical modeling of heat generation and transport in lithium/polymer-electrolyte batteries for electric vehicle applications has been conducted. The results demonstrate that thermal management may not be a serious problem for batteries under low discharge rates. However, under high discharge rates, the temperature of a battery may increase remarkably if the thickness of a cell stack exceeds a certain value. Also, due to the low thermal conductivity of the polymer, the improvement of cooling conditions is not an effective means of improving heat removal for large-stack systems. For a required operational temperature range and a given discharge rate, model predictions can be used to design appropriate battery structures and to choose a suitable cooling scheme.

A mathematical model has been developed to study heat transfer and thermal management of lithium polymer batteries. Temperature dependent parameters including the diffusion coefficient of lithium ions, ionic conductivity of lithium ions, transference number of lithium ions, etc., have been added to a previously developed electrochemical model to more completely characterize the thermal behavior of the lithium polymer system. In addition, experimental studies of the discharge behavior and heat generation rate of lithium polymer cells have been conducted. Comparisons between experimental and mathematical results are presented. Finally different thermal management approaches are discussed. © 2000 The Electrochemical Society. All rights reserved.

The need for energy dense microbatteries with miniature dimensions has prompted the development of unconventional materials, cell geometries, and processing methods. This work will highlight our materials investigations, deposition methods and the device performance of a printed zinc-manganese dioxide rechargeable microbattery utilizing an ionic liquid gel electrolyte. We have developed a direct write dispenser printing method with the ability to fabricate multilayer structures and precisely deposit and pattern these components onto any substrates. The use of a unique room-temperature ionic liquid swelled into a polymer to form a gel electrolyte with solid-like mechanical strength and liquid-like ion transport properties has enabled the simple fabrication of stacked microbattery structures with the potential to be easily integrated directly onto a microdevice substrate. Initial microbattery tests and cycle behavior are discussed, and after an initial activation of the cathode material, an experimental cell discharge capacity and energy density of 0.98 mA h cm −2 and 1.2 mW h cm −2 were measured, respectively.