Robust and durable Li-ion batteries fabricated using lead-free crystalline M2NiMnO6 (where M = Eu, Gd, and Tb) double perovskites

Abstract

Double perovskites with the general formula A₂B₁B₂O₆, in which A₂ is a lanthanide or alkaline earth metal and B₁ and B₂ are transition metals, are famous for their structures and excellent chemical and physical properties. Double perovskites have proven their ability as advanced anode materials for Li-ion batteries (LIB) with advantages in terms of rate capability, lifetime and safety; however, they have not been widely investigated. Therefore, in this work, we fabricated M₂NiMnO₆ (where M = Eu, Gd, and Tb)-based perovskite electrode materials using a simple solid-state reaction method, and they were utilized as anode electrodes in LIBs. The structural, morphological and surface chemical investigations reveal the formation of phase-pure perovskite materials. Among the three types of perovskite materials, Tb₂NiMnO₆ presents outstanding LIB properties, showing an initial discharge capacity of 318 mAh g⁻¹ at a current density of 0.1 Å g⁻¹, which later stabilizes at 110 mAh g⁻¹ in the successive cycles. The cycling stability of the Tb₂NiMnO₆ anode electrode was studied for more than 500 cycles, demonstrating a high structural stability, 70% capacity retention with 0.06% capacity fading per cycle and excellent reversibility of nearly 100% during current rate cycling. Moreover, the Coulombic efficiency (94%) was found to be better than that of commercial graphite (60%), which suffers from sluggish electrochemical kinetics. Thus, the double perovskites studied in this work can be further investigated as alternatives to other established anode electrode materials for future LIBs.