We report on the synthesis and the properties of N,N,N’,N’-tetramethyl-N”,N”-pentamethylenguanidinium bis(trifluoromethylsulfonyl) imide (PipGuan-TFSI). The cation of this novel ionic liquid combines guanidinium and piperidinium structural elements. We tested it for its viscosity, (Li-)ion conductivity, and also for its thermal and electrochemical stability. Furthermore, PipGuan-TFSI with dissolved Lithium TFSI was tested as an electrolyte for Li-ion batteries. These experiments included cycles of Li deposition/dissolution on stainless steel and (de-) intercalation into/from LiFePO4 electrodes. The tests involving LiFePO4 cathodes were performed at various C-rates and temperatures for a better quantitative comparison to other electrolyte systems. We discuss in how far PipGuan-TFSI successfully combines the advantages of guanidinium and piperidinium ionic liquids for battery electrolyte applications.