LiNbO3 coating improves property of LiNi0.5Mn1.5O4 for lithium-ion battery cathode materials

Abstract

Because of high energy density and Co-free, spinel LiNi_0.5Mn_1.5O₄ materials are considered as potential replacement for availably commercial cathodes like LiNi_xMn_yCo_zO₂ (x + y + z = 1) and LiFePO₄. However, the corrosion and interfacial breakdown of electrolyte at high voltage severely limit the extensive application of LiNi_0.5Mn_1.5O₄. In this paper, LiNbO₃ was used as cladding for LiNi_0.5Mn_1.5O₄ cathode material by convenient and feasible wet-chemical technique. The introduction of Nb⁵⁺ into spinel structure usually replaces Mn ions at octahedral site, thus increasing the content of Mn³⁺. Improve the electronic transition channel and electronic transition carrier of LiNi_0.5Mn_1.5O₄ materials. Therefore, while LiNbO₃ cladding layer protects materials from HF attack, the subsurface-rich Mn³⁺ is considered to boost high-rate performance. When the mass ratio of LiNbO₃ coating is 3%, the coating-modified LiNi_0.5Mn_1.5O₄ material exhibits the best property. The specific discharge capacity was 129.2 mAh·g⁻¹ with 93.5% capacity retention rate after 100 cycles at 1 C, the specific discharge capacity reached 116.0 mAh·g⁻¹ at 5 C. Compared with uncoated LiNi_0.5Mn_1.5O₄ material, it shows outstanding electrochemical properties.