Electrochemical performance of a solvent-free hybrid ceramic- polymer electrolyte based on Li 7 La 3 Zr 2 O 12 in P(EO) 15 LiTFSI Marlou Keller a, b , Giovanni Battista Appetecchi a, b, c , Guk-Tae Kim a, b , Varvara Sharova a, b , Meike Schneider d ,J € org Schuhmacher d , Andreas Roters d , Stefano Passerini a, b, * a Helmholtz Institute Ulm (HIU), Helmholtzstrasse 11, 89081 Ulm, Germany b Karlsruhe Institute of Technology (KIT), P.O. Box 3640, 76021 Karlsruhe, Germany c ENEA, SSPT-PROMAS-MATPRO, New Materials for Chemical & Physical Processes Laboratory, Rome, Italy d Schott AG, Hattenbergstraße 10, 55122 Mainz, Germany highlights  Lithium-ion conducting hybrid ceramic-polymer electrolytes.  Effect of LLZO surface contamination on the properties of hybrid electrolytes.  Ion transport in hybrid ceramic-polymer electrolytes. article info Article history: Received 2 March 2017 Received in revised form 31 March 2017 Accepted 4 April 2017 This work is dedicated to Prof. Bruno Scrosati for his 80th birthday Keywords: Lithium Polymer electrolyte Hybrid electrolyte Ceramic-polymer system LLZO ceramic electrolyte abstract The preparation of hybrid ceramic-polymer electrolytes, consisting of 70 wt% of Li þ cation conducting Li 7 La 3 Zr 2 O 12 (LLZO) and 30 wt% of P(EO) 15 LiTFSI polymer electrolyte, through a solvent-free procedure is reported. The LLZO-P(EO) 15 LiTFSI hybrid electrolytes exhibit remarkable improvement in terms of flex- ibility and processability with respect to pure LLZO ceramic electrolytes. The physicochemical and electrochemical investigation shows the effect of LLZO annealing, resulting in ion conduction gain. However, slow charge transfer at the ceramic-polymer interface is also observed especially at higher temperatures. Nevertheless, improved compatibility with lithium metal anodes and good Li stripping/ plating behavior are exhibited by the LLZO-P(EO) 15 LiTFSI hybrid electrolytes with respect to P(EO) 15 LiTFSI. © 2017 Elsevier B.V. All rights reserved. 1. Introduction The societal problems associated with energy, i.e., climate change and fossil fuels' depletion, require the development of a post-oil future. The transportation sector is one of the largest consumers of this polluting, non-renewable and limited resource. The first essential concepts of electric cars were already presented in the 19th century. Very recently these pioneering efforts have regained tremendous interest. Confident predictions presume that electric vehicles (EVs), powered solely by electricity from renew- able energy sources, can replace the internal combustion engines for an emission-free future of transportation. The major drawbacks of EVs are their limited driving range and, crucially, safety. A technology jump from the commercial state-of- the-art Li-ion batteries to all-solid-state batteries is necessary to dramatically reduce the safety issues and, possibly, boost the bat- tery performance. Fires and explosions of lithium-ion batteries are generally related to the flammability of commonly used organic- based, liquid electrolytes. Further problems, which can be elegantly solved by solid electrolytes, are those associated with leakage of liquid components and use of metallic lithium, since thermal runaway may be efficiently suppressed. The efficient and effective use of lithium metal anodes is, in turns, expected to in- crease the energy density of the battery systems making this novel technology promising to considerably improve safety and driving range. * Corresponding author. Helmholtz Institute Ulm, Helmholtzstrasse 11, 89081 Ulm, Germany. E-mail address: stefano.passerini@kit.edu (S. Passerini). Contents lists available at ScienceDirect Journal of Power Sources journal homepage: www.elsevier.com/locate/jpowsour http://dx.doi.org/10.1016/j.jpowsour.2017.04.014 0378-7753/© 2017 Elsevier B.V. All rights reserved. Journal of Power Sources 353 (2017) 287e297