In quest of cathode materials for Ca ion batteries: the CaMO₃ perovskites (M = Mo, Cr, Mn, Fe, Co, and Ni)

Abstract

Basic electrochemical characteristics of CaMO3 perovskites (M = Mo, Cr, Mn, Fe, Co, and Ni) as cathode materials for Ca ion batteries are investigated using first principles calculations at the Density Functional Theory level (DFT). Calculations have been performed within the Generalized Gradient Approximation (GGA) and GGA+U methodologies, and considering cubic and orthorhombic perovskite structures for CaxMO3 (x = 0, 0.25, 0.5, 0.75 and 1). The analysis of the calculated voltage-composition profile and volume variations identifies CaMoO3 as the most promising perovskite compound. It combines good electronic conductivity, moderate crystal structure modifications, and activity in the 2-3 V region with several intermediate CaxMoO3 phases. However, we found too large barriers for Ca diffusion (around 2 eV) which are inherent to the perovskite structure. The CaMoO3 perovskite was synthesized, characterized and electrochemically tested, and results confirmed the predicted trends.

Discovery of Calcium‐Metal Alloy Anodes for Reversible Ca‐Ion Batteries

“…[7,8] (2) Ca is the fifth most abundant element in the earth's crust with an extensive global resource distribution, in contrast to lithium. Material systems including Prussian blue compounds, [10,13,14] Chevrel phases, [15,16] spinels, [17][18][19] perovskites, [20] layered transition metal (TM) sulfides, [21] and iron phosphate, [22] were suggested to be effective Ca-ion electrodes with the spinels and perovskites attracting extra attention because of their predicted high voltage (>3.5 V) and large theoretical capacities (>240 mAh g −1 ) during discharge at room temperature. [9][10][11] The development of CIBs was originally pioneered by the study of Ca-ion electrochemical intercalations into layered transition metal oxides and sulfides.…”

“…(3) The kinetics of Ca-ion in solid electrodes are faster than Mg-and Al-ions due to reduced charge density. [17][18][19][20] Distinct from these TM-based electrodes, a graphite cathode has been reported which functions via the (de-)intercalation of electrolyte salt anions (A − = PF 6 − , ClO 4 − , and so on) upon charge/discharge at remarkably high voltages (4.5-5.6 V) [23,24] with a theoretical capacity as high as 372 mAh g −1 (corresponding to AC 6 ). [12] Subsequently, many efforts then were made to search for cathode materials which will tolerate a large amount of Ca-ions reversibly extracted/ re-accommodated upon charge/discharge.…”

“…[9][10][11] The development of CIBs was originally pioneered by the study of Ca-ion electrochemical intercalations into layered transition metal oxides and sulfides. [17][18][19][20] Distinct from these TM-based electrodes, a graphite cathode has been reported which functions via the (de-)intercalation of electrolyte salt anions (A − = PF 6 − , ClO 4 − , and so on) upon charge/discharge at remarkably high voltages (4.5-5.6 V) [23,24] with a theoretical capacity as high as 372 mAh g −1 (corresponding to AC 6 ). Material systems including Prussian blue compounds, [10,13,14] Chevrel phases, [15,16] spinels, [17][18][19] perovskites, [20] layered transition metal (TM) sulfides, [21] and iron phosphate, [22] were suggested to be effective Ca-ion electrodes with the spinels and perovskites attracting extra attention because of their predicted high voltage (>3.5 V) and large theoretical capacities (>240 mAh g −1 ) during discharge at room temperature.…”

Electrochemical calcium extraction from 1D-Ca3Co2O6

“…18 Besides conventional intercalation hosts like layered TiS2, 19 some appealing compounds potentially exhibiting suitable ion migration pathways within their crystal structure such as CaMoO3 or CaMn2O4 were found to display too large energy barriers for Ca 2+ diffusion. 20,21 Alternative metastable polymorphs, predicted to possess low migration barriers from DFT calculations, 22 do not seem to be achievable even under high pressure and elevated temperatures.…”

A Joint Computational and Experimental Evaluation of CaMn2O4 Polymorphs as Cathode Materials for Ca Ion Batteries

“…First principles calculations are a unique tool to accelerate the identification of materials which could sustain reversible intercalation reactions delivering high specific energy [9][10][11][12][13] . A recent computational investigation of spinel AM 2 as a potential electrode material for Ca ion batteries 14 .…”