Characterization and comparison between different binders applied to Sn based anodes for Lithium ion batteries

S. SMREKAR; D. BARRACO; G. LUQUE; E. PRIMO; J. THOMAS

Buenos Aires

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

International Society of Electrochemistry

Characterization and comparison between different binders applied to Sn-based anodes for lithium ion batteriesSacha Smrekar1, Emiliano N. Primo1, Guillermina Luque2, Jorge E. Thomas3, Daniel E. Barraco11IFEG, Facultad de Matemática Astronomía y Física, Universidad Nacional de Córdoba, CONICET, Ciudad Universitaria, 5000 Córdoba, Argentina.2INFIQC, Departamento de Química Teórica y Computacional, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, CONICET, Ciudad Universitaria, 5000 Córdoba, Argentina.3Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, UNLP, CCT La Plata-CONICET, C.C. 16, Suc. 4 (1900), La Plata, Argentina.Sachasmrekar@gmail.comThe development of new electrodes for lithium ion batteries is a challenge to overcome in order to increase the batteries capacity and allow the introduction of new sustainable technologies. Sn has been proposed as replacement for the commercially used graphite, given that the theoretical capacity of the former (998 mAhg-1) exceeds the capacity of the latter (372 mAhg-1). Nevertheless, before Sn can be successfully used in commercial applications, there are issues that must be addressed. In particular, it has an important volume change (260%) upon lithiation and delithiation, and this process leads to cracking and pulverization of the electrode. Recently, several strategies have been proposed to contain the expansion of Sn without any loss in capacity using new binders and additives. In this work, we study the effect of different types of aqueous polymeric binders in the preparation and performance of Sn-based anodes. Using a Sn/C nanostructured active material, we compare the anodes made with sodium alginate (ALG), sodium carboxymethylcellulose (CMC) at different pHs, and Collagen from common jelly, relative to the standard PVDF binder. Electrochemical cells were assembled in a dry box under argon atmosphere, using lithium foil as counter electrode and reference. The as-prepared electrodes were characterized by charge-discharge galvanostatic cycling to determine the capacity of the electrodes over several cycles. We completed the physicochemical characterization of the electrodes using voltammetry, high current discharge tests and SEM microscopy. We found that the electrodes obtained have higher capacities than commercially used graphite. By using more elastic polymers as binders, we observe the differences in cyclability without significant loses in capacity or electrical contact. The higher elasticity of the aqueous binders allows better accommodation of the active material upon volume change during lithiation and delithiation.