Improvement of electrochemical performance by surface modification of LiNi0.65Co0.15Mn0.2O2 cathode materials with SnO2

Abstract

LiNi_0.65Co_0.15Mn_0.2O₂ batteries have attracted more and more attention due to their high energy density. However, LiNi_0.65Co_0.15Mn_0.2O₂ possesses adverse factors such as severe Li-Ni mixing and side reactions between active substance and electrolyte, which limits its electrochemical performance. Hence, we employed the SnO₂ surface coating method to enhance its performance. SnO₂ coating inhibits the direct contact between LiNi_0.65Co_0.15Mn_0.2O₂ and the electrolyte, which reduces the lithium-nickel mixing, enlarges the lithium layer spacing, and contributes to the improvement of the specific capacity of discharge and the cycling performance. The electrochemical results indicate the optimal SnO₂-coated LiNi_0.65Co_0.15Mn_0.2O₂ show excellent cycling performance (85.0 % capacity retention for 100 cycles at 0.1 C) and multiplicative performance (124.1 mA·h·g⁻¹ discharge specific capacity at 2 C). The paper highlights the SnO₂ cladding technology which provides an excellent research idea to improve lithium-ion batteries.