As the name indicates, metal-air batteries are energy storage devices in which one of the electrodes, the anode, is formed by a metal and the other, the cathode, by air. These batteries promised a leap in capacity as compared to the current ones. The improvement should enable the fabrication of devices with superior performance and same size, or with similar performance and lower size and cost.

As metal-air batteries are in development stage, several studies need to be conducted to understand them in detail and optimize them for each application. However, to conduct these experimental studies, the instrumentation available is not always adequate.

A group of researchers and students linked to CINE’s Advanced Energy Storage Division was studying metal-air batteries (more precisely, lithium-oxygen batteries), when they faced with the need to develop a device to analyze, in real time, what happens on the surface of electrodes while the battery is running. This type of equipment already existed, but none allowed to control the atmosphere in the electrode, which is an essential requirement in the study of metal-air batteries.

After developing five generations of devices, the team could eventually meet all the needs. At the end of 2020, the team filed a patent application to protect the invention and, occasionally, license it to an interested party.

The invention could be used by researchers from research institutions or the industry who work with electrodes which require a controlled atmosphere.

The device is a hermetic electrochemical cell with windows which can be changed in function of the technique of analysis one wishes to use. Additionally, they permit the controlled passage of gases. With these characteristics, the equipment can characterize the changes which occur in the electrodes and their catalysts during the electrochemical reactions proper to the batteries, in real time, and without needing to expose the electrodes to contamination by taking them to different characterization instruments.

In fact, one of the differentials of the equipment is the possibility of admitting different characterization techniques, such as Raman, DRX, FTIR and XAS spectroscopy, which bring complementary information on the composition, morphology and structure of the electrodes. Through the windows, which are especially developed, incidence of the radiation which interests is possible so that, upon coming into contact with the electrode, this light supplies the information one wishes to obtain. Additionally, the device was projected so that the analyses can be made in the experimental stations of a synchrotron laboratory, where the techniques yield more accurate results.

The team responsible for the development of the device is formed by UNICAMP professors Gustavo Doubek and Rubens Maciel Filho, the post-docs Thayane Carpanedo de Morais Nepel and Chayene Gonçalves Anchieta, and the PhD students André Navarro de Mirando and Letícia Frigerio Cremasco – all active members of CINE.

Patent: André Navarro de Miranda, Gustavo Doubek, Letícia Frigerio Cremasco, Thayane Carpanedo de Morais Nepel, Chayene Gonçalves Anchieta, Rubens Maciel Filho. Dispositivo eletroquímico para caracterização de eletrodos em regime dinâmico de operação. UNICAMP. BR 10 2020 026298. 21 de dezembro de 2020.