ИСТИНА

HIGH-VOLTAGE CATHODE MATERIALS AND ELECTROLYTES FOR ME-ION BATTERIES O.A.Drozhzhin1,2 1 Lomonosov Moscow State University, Leninskie gory 1, Moscow, 119991 Russia 2 Skolkovo Institute of Science and Technology, 143025, Moscow, Russia drozhzhin@hotmail.com Modern Li-ion batteries provide up to 200-250 Wh/kg of the specific energy density. Despite this value is the highest among widely-used commercially available electrochemical power sources, industry needs further improvements. There are three main direction of the possible increase of LIB capacity: 1) Increasing specific capacity of both cathode and anode materials 2) Decreasing mass fraction of the support (inactive) components of the battery 3) Increasing average working voltage. Most of the cathode materials used for LIB mass production operate within 2.5-4.3 V vs. Li/Li+ voltage window; average working potential is ~ 3.7 V (LCO, NMC, NCA), ~ 4.0 V (LMO) or ~ 3.4 V (LFP). However, a number of well-known cathode materials may provide up to 5.0 V or even higher working voltage: LiNi0.5Mn1.5O41, LiCoPO42, Li2CoPO4F3 etc. Such potential should result in a 30-50% growth of the specific energy density of the batteries. Nevertheless, industrial use of these and other high-voltage materials is strongly hampered by poor cycle life of such electrochemical systems. Intense studies devoted to developing of the stable high-voltage Li-ion electrolyte are being carried out to address this issue. Most of them may be in turn divided into three main directions: 1) Introducing stable solvents which demonstrate oxidative stability up to 5-5.5 V vs. Li/Li+ 2) Introducing specific salts or addictives which make electrolyte or interface chemically stable, including “superconcentrated” electrolytes 3) Introducing principally different concepts such as solid electrolytes Every direction is characterized by its specific pros and cons. In most cases the challenge is complicated by need for developing the whole electrochemical system, e.g. cathode, electrolyte, anode, current collectors, separator etc. All the issues relating to such studies will be discussed in the presentation. References 1. Qiming Zhong, Arman Bonakdarpour, Meijie Zhanga, Yuan Gao and J. R. Dahn, Synthesis and Electrochemistry of LiNixMn2−xO4, J. Electrochem. Soc., 1997, volume 144, 205-213 2. K. Amine, H. Yasuda and M. Yamachi, Olivine LiCoPO4 as 4.8 V  Electrode Material for Lithium Batteries, Electrochem. Solid-State Lett., 2000, volume 3, 178-179 3. S. Okada, M. Ueno, Y. Uebou, J.-i. Yamaki, Fluoride phosphate Li2CoPO4F as a high-voltage cathode in Li-ion batteries, Journal of Power Sources, Volume 146, Issues 1–2, 26 August 2005, Pages 565-569