New lithium borates with bistetrazolato(2-) and pyrazinediolato(2-) ligands - potentially interesting lithium electrolyte additives

摘要

We present a convenient synthesis of the first silylated bistetrazole via a catalyzed twin [2 + 3] cyclo-addition of TMS-azide at cyanogen and its application to access bistetrazolatoborates, structurally characterized by a unique unsaturated ten-membered B2N4C4 heterocyclic system. Furthermore, new borate anions with two pyrazine-2,3-diolato ligands were synthesized from tetrafluoroborate salts and structurally characterized. Their organic cation can be exchanged for Li+ via cation exchange. The conceptual relation of these new salts to lithium ion battery bisoxalalatoborate additive LiBOB, a prominent solid electrolyte interface (SEI) generator, is discussed.