Interfacial phenomena in lithium ion polymer batteries result in capacity fade upon cycling due to a number of reasons, with the major one being the poor electrode/electrolyte interface. This leads to poor chemical and electrochemical stability of the electrolyte, i.e. decomposition, electrode passivation, etc. In this paper, we describe a model system, which we have applied to a lithium ion battery for improving compatibility between electrodes and electrolytes in a truly solid-state system. This involved the fabrication of plasticizer-free multi-layered polymer electrolytes wherein the different layers have different compatibility characteristics with the electrodes. These characteristics include morphology, ionic and electronic mobility within the whole cell. Preliminary results using this approach are described. (C) 2001 Elsevier Science B.V. All rights reserved.