A cost effective and reliable technology for the fabrication of electrochemical test-cell arrays for battery materials research, based on batch-fabricated glass micro packages was developed and tested. Jet dispensing was investigated for the first time as a process for fabricating battery electrode arrays and separators and compared to micro dispense printing. The process shows the reproducibility over the whole range of investigated materials and battery cell structures that is required for battery materials research. Such setup gives rise to a significantly improved reliability and reproducibility of electrochemical experiments. Cost-effective fabrication of our test chips by batch processing allows for their single-use in electrochemical experiments, thereby preventing contamination issues due to repeated use as in conventional laboratory test cells. In addition, the integration of micro pseudo reference electrodes is demonstrated. Thus, the test cell array together with the developed electrode/electrolyte deposition technology provide a highly efficient tool for speedy combinatorial and high throughput testing of battery materials on a system level (full cell tests). Experimental results are shown for the microfabrication of lithium-ion test cells with help of several electrode and binder materials. The influence of jetting parameters on electrode lateral dimensions and thickness, reproducibility of the electrode mass as well as the use of integrated micro-reference electrodes for impedance spectroscopy and cyclic voltammetry measurements in micro cells are presented in detail.

No abstract

No abstract

For the first time, electrophoretic deposition (EPD) has been employed to prepare a self-supported, inorganic membrane consisting of SiO 2 nano-fibers, as a separator for lithium-ion batteries. The SiO 2 nano-fibers that were fabricated by a lowcost force spinning technique were deposited by EPD directly onto LiNi 0.8 Co 0.15 Al 0.05 O 2 cathode material. Citric acid charging agent and anhydrous acetone solvent were used. The resulting porosity and tortuosity of the EPD SiO 2 separator were 71.42 %, and 1.70, respectively. The slightly higher tortuosity of the EPD-SiO 2 -fiber separator (60 μm) led to a lower rate capability in comparison to commercial GF/A glass fiber separator (260 μm). On the other hand, the latter exhibited lower self-discharge than the former in full-cells with a graphite anode; this is proposed to be related to the different purities of the two materials that impart different electronic properties or the presence of 20 wt % PVDF in the EPD-SiO 2 separator. Indeed, the deposited membrane has good characteristics as a battery separator and the EPD process is extremely feasible for the fabrication of miniaturized lithium-ion batteries on wafer level.[a] Dr.

No abstract

No abstract

A technology has been developed for the extreme miniaturization of lithium ion micro batteries using wafer level processing. These batteries will be used as electronic buffer storage in future miniaturized sensor nodes, data loggers, RFID devices and medical applications. Between 2000 and 10000 micro batteries can be fabricated on one 300 mm wafer being a low cost process. While standard silicon processing used in MEMS and 3D packaging can be used to define cavities for the electrochemical electrodes, current collectors and contacts, technology development was required to optimize the electrode pastes and electrolyte for application in the wafer processing. A novel battery design was tested with anode and cathode fabricated side by side in a planar arrangement which simplifies battery assembly significantly

A technology has been developed for the extreme miniaturization of lithium ion micro batteries using wafer level processing. These batteries will be used as electronic buffer storage in future miniaturized sensor nodes, data loggers, RFID devices and medical applications. The micro batteries can store the energy generated by energy harvesters which are a prerequisite for energy autarkic wireless sensor nodes and enable the technology for ambient intelligence and the internet of things.Between 2000 and 10000 micro batteries can be fabricated on one 300 mm wafer, being a low cost process. Process optimization of silicon processing was necessary to define cavities for the electrochemical electrodes, current collectors and contacts. The active masses are applied by means of dispensing. Technology development was required to optimize the electrode pastes and electrolyte for application in micro channel structures. Thus a wide variety of state of the art electrode materials can be used and the battery parameters can be tailored according to their application.A novel battery design was tested with anode and cathode fabricated side by side in a planar arrangement. Electrode width and depth as well as electrolyte thickness are the main design parameters to achieve sufficient current capability which is required for wireless sensor nodes.