Studies of Nickel-Rich LiNi0.85Co0.10Mn0.05O2 Cathode Materials Doped with Molybdenum Ions for Lithium-Ion Batteries

Francis Amalraj Susai; Daniela Kovacheva; Tatyana Kravchuk; Yaron Kauffmann; Sandipan Maiti; Arup Chakraborty; Sooraj Kunnikuruvan; Michael Talianker; Hadar Sclar; Yafit Fleger; Boris Markovsky; Doron Aurbach

doi:10.3390/ma14082070

Studies of Nickel-Rich LiNi_0.85Co_0.10Mn_0.05O₂ Cathode Materials Doped with Molybdenum Ions for Lithium-Ion Batteries

Materials (Basel). 2021 Apr 20;14(8):2070. doi: 10.3390/ma14082070.

Affiliations

¹ Department of Chemistry, Institute for Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan 52900, Israel.
² Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria.
³ Solid State Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel.
⁴ Department of Materials Science and Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel.
⁵ Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.

Abstract

In this work, we continued our systematic investigations on synthesis, structural studies, and electrochemical behavior of Ni-rich materials Li[Ni_xCo_yMn_z]O₂ (x + y + z = 1; x ≥ 0.8) for advanced lithium-ion batteries (LIBs). We focused, herein, on LiNi_0.85Co_0.10Mn_0.05O₂ (NCM85) and demonstrated that doping this material with high-charge cation Mo⁶⁺ (1 at. %, by a minor nickel substitution) results in substantially stable cycling performance, increased rate capability, lowering of the voltage hysteresis, and impedance in Li-cells with EC-EMC/LiPF₆ solutions. Incorporation of Mo-dopant into the NCM85 structure was carried out by in-situ approach, upon the synthesis using ammonium molybdate as the precursor. From X-ray diffraction studies and based on our previous investigation of Mo-doped NCM523 and Ni-rich NCM811 materials, it was revealed that Mo⁶⁺ preferably substitutes Ni residing either in 3a or 3b sites. We correlated the improved behavior of the doped NCM85 electrode materials in Li-cells with a partial Mo segregation at the surface and at the grain boundaries, a tendency established previously in our lab for the other members of the Li[Ni_xCo_yMn_z]O₂ family.

Keywords: LiNi0.85Co0.10Mn0.05O2 cathode materials; Mo-doping; cycling behavior; dopant segregation at the surface; lithium-ion batteries.