Lithium transfer dynamics and storage capacity/cyclability properties of Ni and Ru dual-doped two-dimensional FePS3 nanoflakes

Abstract

Despite owning a high theoretical lithium ion capacity, the iron phosphorus trisulfide FePS3 writhes from inferior cyclability and lower reaction kinetics to be employed as a potential anode in lithium ion batteries. Herein, we demonstrate a dual-doping approach with nickel and ruthenium in optimal quantities leading to the formation of Ni0.07Ru0.03-FePS3 two dimensional layers (flakes) having high electrochemical conductivity and increased cyclability. This comprehensive investigation unravels the influence of single and dual doping of isovalent (Ni2+) and aliovalent (Ru3+) ions on the lithium intercalation/deintercalation kinetics in FePS3. The Ni increases active intercalation sites and enhances electrical conductivity while Ru influences the Li+ ion kinetics by increasing the channel width, termed as pillar effect. Theoretical calculations indicate the improved binding of lithium on Ni and Ru dual-doped FePS3. Ni0.07Ru0.03-FePS3 based anode offers a high discharge-capacity ∼600mAhg−1 (∼450 mAhg−1) at a high current rate of 1 Ag−1 (10 Ag−1) showcasing an approximate six-fold improvement from FePS3 (∼104 mAhg−1). The high coulombic efficiency (∼95 %) and high rate performance with improved cyclability obtained with the LiFePO4/Ni0.07Ru0.03-FePS3 full-cell indicate the synergistic effects of dual doping. This opens a plethora of opportunities in developing high-capacity and high-cyclability anodes by engineering the metal trichalcogenides through dual doping.