Other types of ceramic-polymer systems

Also the introduction of electronically conducting fillers at loadings below the percolation threshold was done leading to enhanced transport 

An attempt to introduce macroscopic anions was made. When cation exchanging clays were introduced into the polymer, some lithium cations were liberated into the polymeric phase and contributed to ionic transport. Negatively charged clay particles, being of macroscopic size, could not move and in this way the lithium transport number could be significantly increased (Aranda and Ruiz-Hitzky 1992 Chen and Chang 2001 Kim and Park 2007 Kim et al 2008 Krawiec et al 1995 Riley et al 2002,2003 Sand et al 2005 Vaia et al 1995 Walls et al 2003). 

Some extended works have been devoted to studies on the influence of highly acidic fillers (both soluble such as AlBrs or AlCh and ceramic ones) on the properties of gel polymer electrolytes based on PVdF. It was found that the conductivity and cation transference numbers increase on the addition of these strong Lewis acids. Also the stability of the interface with lithium metal is enhanced however, in the case of aluminium halides the reactions with organic carbonates can take place and affect the properties of such systems on prolonged storage (Stolarska et al. 2007 Walkowiak et al. 2006,2007). 

Recent work in the field of ceramic polymeric electrolytes is the so-called polymer-in-ceramic approach presented by Syzdek et aL (2009). It consists of introducing polymer-salt complexes into porous ceramic structures. In this manner we split the spatial and electronic separation and ionic conductivity into two phases again, but the difference is that ceramics are much more thermally stable, resistant to reactions with lithium and to puncturing with lithium dendrites that can appear in the cell. Also the wettability of ceramic materials is much better than that of polymers, therefore this approach can be considered as an alternative to the Bellcore process that 

The impact of fillers on the ionic conductivity of solid PEO-based systems has been a subject of discussion for quite many years. The literature shows that for some systems the enhancement of conductivity is tremendous, although for some others it is very limited or there is even no enhancement of transport properties at aU. Some systems are stable, some are not, although they differ only slightly. A deeper look into the subject, combined with extended laboratory practice prove that ceramic fillers work, but the extent to which it happens depends a lot on the preparation conditions. 

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