Site Selectivity in Doped Layered and Spinel Cathode Materials for Li-Ion Batteries

Abstract

In this work, a simple and effective method was proposed to determine the site selectivity of cation dopants in layered and spinel cathode materials for Li-ion batteries on the basis of ionic electronegativity and ionic radius. The dopant occupancy can be predicted by comparing the combined deviation degree of electronegativity and radius between the dopant and the substituted ion, and dopants prefer to occupy the site where the deviation degree is the least. Based on this method we predicted the preferred occupancy sites of 38 frequently used ions doped in layered LiV 3 O 8 and spinel LiMn 2 O 4 , which agree well with the available experimental and other calculated results. The present work provides a useful method to predict the site selectivity of cations doped in inorganic crystals, and further helps us to design high performance cathode materials for Li-ion batteries.

Anion Substitution to Suppress the Voltage Hysteresis of Na3MnTi(PO4)3 as a Cathode Material for Sodium-Ion Batteries

“…26−28 It is known that the cation tends to occupy the site where the substituted ion and the cation have similar EN and ionic radius. 35,36 The deviation degree (D) is defined by combining the relative deviation of EN and ionic radius of the cation from the substituted ion. 35,36 The occupancy selectivity of Mn 2+ on the Na1 and Na2 vacancies can be evaluated by the D value via eq 1.…”

“…35,36 The deviation degree (D) is defined by combining the relative deviation of EN and ionic radius of the cation from the substituted ion. 35,36 The occupancy selectivity of Mn 2+ on the Na1 and Na2 vacancies can be evaluated by the D value via eq 1. 26,27,35,36…”

Effect of Solvothermal Parameters on Electrochemical Performance of -LiFeO<SUB>2</SUB>

“…[1][2][3] Lithium-ion batteries (LIBs) are expected as successful energy storage systems, 4 5 which have been widely commercialized for their high energy storage density, long cycle life, negligible memory effect and many other advantages. 6 7 LiCoO 2 is the most widely used cathode material in commercial LIBs at present by virtue to its high reversible capacity (130-150 mAh/g), long cycle life (300-500 cycles) and easy preparation.…”

Improved Performance of Na3TiMn(PO4)3 Using a Non-stoichiometric Synthesis Strategy

“…Both M1 and TM sites can be occupied by Mn 2+ . The empirical formula can predict the preferred site by comparing the deviation degrees ( D ) of ionic EN and radius between the dopant and the replaced elements as follows: − χ M and r M represent the EN and radius of the dopant, respectively, and χ M1(2) and r M1(2) are the EN and radius of the replaced ion 1 or 2. For Mn 2+ to replace Na + or Ti 4+ , D Na + and D Ti 4+ can be calculated to be 0.42 and 0.64, respectively, by using the reported ionic EN and radii of Mn 2+ , Na + , and Ti 4+ . , The smaller value of D Na + than D Ti 4+ implies that Mn 2+ and Na + have higher similarities than Mn 2+ and Ti 4+ in terms of ionic EN and radius, implying that the Na + site is favorable for Mn 2+ to occupy, leading to Na + /Mn 2+ cation mixing in the M1 site.…”