High Performance Lithium-Ion Polymer Cells Assembled with Composite Gel Polymer Electrolytes Based on Core-Shell Structured SiO2(Li+) Nanoparticles

Gel polymer electrolytes have been considered as one of the most promising electrolyte materials for rechargeable lithium batteries. However, the host polymers lose mechanical strength when plasticized by organic solvents.  In order to obtain the gel polymer electrolytes with improved electrical and mechanical properties, inorganic fillers such as SiO₂, Al₂O₃, TiO₂ and BaTiO₃ have been incorporated into host polymers [1,2]. The addition of inorganic fillers improves ionic conductivity of polymer electrolytes and interfacial properties. In these composite gel polymer electrolytes, the inorganic particles promote electrochemical properties of the polymer electrolytes through physical actions without directly contributing to the lithium ion transport process.  It is of our interest to synthesize and introduce inorganic materials containing dissociative lithium ions [3].  In this study, we prepared the composite gel polymer electrolytes based on core-shell structured SiO₂ nanoparticles containing a lot of lithium ions which can also act as the source of charge carriers.  The composite gel polymer electrolyte exhibited high ionic conductivity, high Li⁺transport number, good mechanical strength to prepare thin films (~25 μm) and favorable interfacial characteristics.  Lithium-ion polymer cells assembled with the composite gel polymer electrolytes were characterized by high capacity and good capacity retention at high temperature as well as ambient temperature.

 

[References]

[1] F. Croce, G.B. Appetecchi, L. Persi, B. Scrosati, Nature 394 (1998) 456.

[2] S.K. Das, S.S. Mandal, A.J. Bhattacharyya, Energy Environ.Sci. 4 (2011) 1391.

[3] Y.S. Lee, S.H. Ju, J.H. Kim, S.S. Hwang, J.M. Choi, Y.K. Sun, H. Kim, B. Scrosati, D.W. Kim, Electrochem. Commun. 17 (2012) 18.