Development of improved lithium-ion batteries (LIB) by using charged lithium ion containing organic microporous polymer networks as a polyelectrolyte

• Applicant: Dr. Sabrina Fischer
• Subject Area: Physical Chemistry of Solids and Surfaces, Material Characterisation
• Term: from 2016 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 289499427

A LIB is built up of electrodes, often a graphite anode and a lithium metal oxide cathode such as LiCoO2 or LiMn2O4 and an electrolyte which ensures the lithium ion transport from one to the other electrode. The coordination of the ions within electrolytes is crucial for the lithium ion conductivity and consequently for the energy density of the LIB. For that reason, weakly coordinating anions, so-called WCAs especially borates, were often used as counter ions to lithium ions. Charged microporous polymer networks called Li-ABNs consist of cross-linked anionic WCA units having an extremely weak coordination to the incorporated lithium ions within the pores. In addition, a new synthesis will be presented for the formation of a novel soluble charged microporous polymer network on the principle of PIMs. This polymer called WCA-PIM should be consisted of spirobifluorene and borate WCA units with lithium ions within the pores. Due to the good solubility of this polymer in solvents, the preparation of membrane films can be simplified. Additionally, gel polymer electrolytes will be prepared by swelling the polymers in solvents. A high ionic conductivity of the lithium ions for these polymers is expected. Therefore, these polymers represent suitable polyelectrolytes. By using such polymers as electrolytes, an improvement in safety, energy density and lifetime of these novel LIBs is predicted.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professorin Dr. Sarah H. Tolbert