Multi-Stage Engineered Co-Free Li[Ni1-X-Y Ti x Al y ]O2 Cathode for High-Energy Li-Ion Batteries

Abstract

Since the global blueprint for carbon net zero emissions has been drawn, a part of the internal combustion engine (ICE) market share of vehicles has been continually shifting toward electric powered public and personal transportation. However, the serious remaining challenges regarding the price and performance issues of lithium-ion batteries (LIBs), which are the primary power source for electric vehicles (EVs), have impeded the large-scale adoption of EVs. Solving the affordability issue of current layered cathodes requires reducing the reliance on Co, which is extremely expensive with supply uncertainty. The aim of developing Co-poor or Co-free cathodes has led to an interest in LiNiO2 (LNO).1 LNO is one of the most promising cost-effective Co-free cathodes for LIBs because the cathode can achieve a high specific capacity of over 250 mAh g-1 with a typical upper voltage of 4.3 V versus Li/Li+. However, its poor cycling durability and thermal instability make its practical use difficult.2 In this study, we propose a highly stable Co-free Ni-enriched layered cathode based on LNO through a new doping strategy that incorporates heteroelements at different doping stages, i.e., the introduction of Ti during Ni(OH)2 synthesis and doping excess amounts of Al during the lithiation step. In combination with cathode surface protection, i.e., electrolyte modification or cathode surface coating, the proposed cathode retains 72.0% of its initial capacity after 3,500 cycles, which is the state-of-the-art for Co-free layered cathodes. Reference s : [1] M. Bianchini, M. Roca-Ayats, P. Hartmann, T. Brezesinski, J. Janek, Angew. Chem. Int. Ed., 58 (2019) 10434-10458.[2] H.-J. Noh, S. Youn, C.S. Yoon, Y.-K. Sun, J. Power Sources, 233 (2013) 121-130.