ИСТИНА

Exponentially growing energy consumption and increasing demands of technology put forward additional strict specifications to rechargeable batteries. Much attention is focused on search and investigation of new perspective materials with enhanced electrochemical properties, namely energy density, rate capabilities and cycling performance. Fluoride-phosphates with a general formula of A2MPO4F (A – alkali metal, M – 3d transition metal) were recognized as a perspective class of high-energy cathode materials for rechargeable batteries of various large-scale and grid applications. Indeed, phosphate-groups along with fluorine in the structure give rise to a significant potential raise in comparison to oxide materials; a theoretical possibility to extract more than one alkali ion from the lattice makes us expect a higher specific capacity; moreover, a weaker affinity of lithium towards fluorine than oxygen along with solid-solution intercalation mechanism forecast a faster ion transport in the cell [1]. A2Co1-xMxPO4F solid-solutions attracted our attention owing to the possibility to adjust the high operating voltage to values sustained by conventional electrolytes when substituting of Co by Mn or Fe with lower M3+/M2+ redox potential and tuning of the crystal structure. The other reason for the examination of these solid-solutions is a real challenge to bring more than one alkali ion per formula into a reversible de/intercalation process [2]. Thus the aim of this work is synthesis and investigation of A2Co1-xMxPO4F fluoride-phosphates cathode materials. This work was supported by Skolkovo Institute of Science and Technology, Russian Foundation of Basic Research (grant No. 13-03-00495a) and the Lomonosov Moscow State University Program of Development up to 2020 [1] E. V. Antipov, N. R. Khasanova, S. S. Fedotov, IUCrJ, 2 (2015) 85 [2] N. R. Khasanova, O. A. Drozhzhin, S. S. Fedotov, D. A. Storozhilova, R. V. Panin, E. V. Antipov, Beilstein J. Nanotechnol., 4 (2013) 860.