Nanoparticles of complex oxides Li_{1 + x} (Ni _y Mn _z Co_{1 – y – z} )_{1 – x} O_{2 – δ} (0 ≤ x ≤ 0.2, 0.2 ≤ y ≤ 0.6, 0.2 ≤ z ≤ 0.4) obtained by thermal destruction of metal-containing compounds in oil

Abstract

Cathode materials in the form of Li_{1 + x} (Ni _y Mn _z Co_{1 – y – z} )_{1 – x} O_{2 – δ} (0 ≤ x ≤ 0.2, 0.2 ≤ y ≤ 0.6, 0.2 ≤ z ≤ 0.4) core–shell nanoparticles coated with a thin carbon shell were synthesized by thermal destruction of metal-containing compounds in oil and studied. The results of element analysis, X-ray diffraction analysis, scanning electron microscopy, X-ray photoelectron spectroscopy, and electrochemical tests of cathodes based on the obtained complex oxides in model cells were presented. The complex oxide Li_1.2Ni_0.2Mn_0.4Co_0.2O_1.9 was the most promising composition because the loss of capacity after 50 cycles was 4% at a current density C/2 and an operating potential of 3.0–4.4 V relative to E (Li/Li⁺). When the current density in discharge increased sixfold (3 C), the loss of capacity was 14% relative to the value obtained at a discharge current C/2 at voltages 3.0 to 4.4 V.