Tetrapyrrolic Organic Polymers Cathodes for Lithium Ion Batteries

OTERO, LUIS; SUÁREZ, BELÉN; SOLIS, CLAUDIA; GERVALDO, MIGUEL; OTERO, MANUEL; SIGAL, AGUSTÍN; LEIVA, EZEQUIEL P.M.; BALLATORE, M. BELÉN; MILANESIO, ELISA; BAIGORRIA, ESTEFANÍA; DURANTINI, EDGARDO N.

Buenos Aires

Congreso; 20th Topical Meeting of the International Society of Electrochemistry; 2017

International Society of Electrochemistry

Due to the relatively slow intercalation kinetics of Li+ in most of the inorganic cathode materials in lithium ion batteries (LIB), these conventional cathodes exhibited low rate performance, which is one of the most important challenges for its practical applications. For the development of the next generation of green batteries, it is necessary to develop fast, high energy density and heavy metal-free cathode materials. Several studies have revealed that organic cathode materials (formed by organic molecules and polymers) are promising for (LIB) development and application, because of their high energy and power densities, fast charge-discharge cyclability, structural variety, resource renewability and environmental friendliness [1]. Additionally, the organic materials possesses advantages that are not easily available for inorganic compounds. They are potentially low-cost, because no expensive elements are involved, easily recyclable, and can be specifically designed to achieve the needed characteristic for the devices application. Also, a common procedure for inorganic intercalation compounds production such as high-temperature annealing, is not required for organics materials. These organic compound-based cathode materials for (LIB) mainly include organosulfur compounds, organic carbonyl compounds, conducting polymers, and organic free radical compounds [1]. However, the dissolution of small organic molecules in nonaqueous electrolyte will lead to the fast declining of electrochemical capacity of the organic electrode, which is one of the most problems in practical applications. In this frame, the development of synthetic routes allow the generation of organic compounds with the desired physical properties for application as building blocks of electronic devices. In this context it deserves special consideration the use of organic conducting polymers, which in general are insoluble in most solvents. It is reasonable to expect that the development of organic polymers with adequate electronic properties will introduce a significant advance in the construction and application of devices for energy storage. On the other hand, tetrapyrrolic compounds such as metal phthalocyanines were extendedly studied as electrode material for Li batteries, and iron phthalocyanine demonstrated high energy density (2300Wh kg-1 at a rate of 0.3 mAcm-2 [2]). In this work, we shows our preliminary results of the use of electrochemically synthetized tetrapyrrolic organic polymers as cathodes for (LIB). 5,15-bis[4-(N,N-diphenylamino)phenyl)]-10,20-bis[3-(N-ethylcarbazoyl)]porphyrin (PCBZTPA) and Zn(II) 5,15-bis[4-(N,N-diphenylamino)phenyl)]-10,20-bis[3-(N-ethylcarbazoyl)] porphyrin (PCBZTPA-Zn, Fig. 1). Upon oxidation, both carbazol (CBZ) and triphenylamine (TPA) moieties undergo the well-known radical cation dimerizations producing dicarbazol (DCBZ) and tetraphenylbenzidine (TPB) units, which conduct to porphyrin polymer formation (Figure 2). This conducting polymers were tested in a 3 electrodes swagelock cell using metallic lithium as counter and reference electrodes. The materials exhibited moderate charge storage and adequate cyclability.