Na+-doped layered LiNi1/3Co1/3Mn1/3O2 cathode derived from low nickel matte with high structural stability and fast diffusion kinetics
(State Key Laboratory of Advanced Special Steel, School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China)
Abstract: Sodium ion (Na+)-doped Li1-xNaxNi1/3Co1/3Mn1/3O2 (NCM-Na) cathode materials with enhanced stability were synthesized using a co-precipitation method. The results demonstrate the feasibility of extracting nickel from low nickel matte as a nickel source for synthetic raw materials. Subsequently, the optimal content of Na+ is introduced in advance to occupy partially lithium-ion sites in NCM (Ni, Co, Mn) materials synthesized by chemical reagents, which achieves a stable structure with lower Li+/Ni2+ mixing and improved electrochemical performance. When the dopant content of Na+ is 1 wt.% (x=0.01), the capacity retention ratio of the produced NCM-Na cathode increases from 76.84% to 89.21% after 100 cycles (at 1C). In particular, a specific capacity of 110 mA·h·g-1 is maintained after 200 cycles (at 5C). These results demonstrate that coupling materialization metallurgy and heteroatomic doping are promising strategies for the development of low-cost and high-performance LiNi1/3Co1/3Mn1/3O2 cathodes for advanced lithium-ion batteries.
Key words: lithium-ion batteries; LiNi1/3Co1/3Mn1/3O2 cathode; Na+-doping; diffusion kinetics; low nickel matte