The structural and electrochemical characteristics and the thermal behavior of four-cation oxides, LiNi0.85Co0.10M0.05O2 (M=Al, Fe) were examined by X-ray and neutron diffraction measurements, charge/discharge cycling and thermal analysis. LiNi0.85Co0.10Al0.05O2 showed enhanced electrochemical properties, i.e. a small polarization and a large reversible capacity during the charge/discharge cycling compared with LiNiO2 and it is due to the structural stabilization of the nickelate in the wide range of x by Co and Al substitution. The substitution of Co, Al and Fe also had a beneficial effect on the thermal stability of LiNiO2.