Layered Fe-Substituted LiNiO₂ Electrocatalysts for High-Efficiency Oxygen Evolution Reaction

Abstract

LiNi 1 − x Fe x O 2 (0 ≤ x ≤ 0.3) and Li y Ni 0.8 Fe 0.2 O 2 (0.8 ≤ y ≤ 1.2) catalysts for the oxygen evolution reaction (OER) were systematically investigated to discover the influence of the composition and layered structure on electrochemical activity. LiNi 0.8 Fe 0.2 O 2 exhibits OER activity that is better than that of LiNiO 2 and other Fesubstituted LiNiO 2 catalysts, while Li 1.2 Ni 0.8 Fe 0.2 O 2 shows OER activity that is much higher than that of LiNi 0.8 Fe 0.2 O 2 and Li 0.8 Ni 0.8 Fe 0.2 O 2 . The best OER activity is achieved on Li 1.2 Ni 0.8 Fe 0.2 O 2 with a Tafel slope of 59 mV dec −1 and a current density of 10 mA cm −2 at an overpotential of 302 mV, better than that for the benchmark IrO 2 catalyst. Combined with the density functional theory calculations, the enhanced OER activity is mainly attributed to the unique electronic structure derived from the interaction of Li, Ni, and Fe in the materials and the layered structure which plays an important role in stabilizing the high valence states of Ni and Fe during the OER.

Application of In Situ Techniques for the Characterization of NiFe‐Based Oxygen Evolution Reaction (OER) Electrocatalysts

“…However,their largescale applications are greatly limited by their low reserves and high prices. [17,18] Accordingly,e xtensive efforts have been devoted to develop highperformance and earth-abundant electrocatalysts for OER, such as perovskite oxides, [19][20][21][22] spinels, [23][24][25] the layer structure materials, [26][27][28] metal borides, [29] metal carbides, [30,31] metal chalcogenides, [9] metal pnictides, [32][33][34] organometallics, [35] and non-metal materials. [36,37] In particular,l ayered NiFe oxides/hydroxides have been demonstrated as the most active catalysts in alkaline electroyltes.…”

Review of Modified Nickel-Cobalt Lithium Aluminate Cathode Materials for Lithium-Ion Batteries

“…However, it is still impossible to synthesize a stoichiometric ratio of LiNiO 2 by a simple process because Ni 2+ is difficult to completely oxidize to Ni 3+ , and its electronic structure, magnetic structure, and local structure are still highly controversial, severely limiting this positive electrode from practical applications. It is feasible that a layered nickel-rich oxide replacing Ni with other heteroatoms, such as Co [10,11], Fe [12,13], Mn [14,15], Ti [16], Zr [17], Mg [18], and Al [19], can deliver a sizeable reversible capacity, and it is one of the most attractive strategies in the field of cathode materials. These substitutions mainly affect the layered crystal structure, the electrochemical stability, and the capacity with the intercalation and deintercalation of lithium ions, especially for the thermal stability in the case of extreme charge-discharge processes.…”

Rose‐like Nanocomposite of Fe‐Ni Phosphides/Iron Oxide as Efficient Catalyst for Oxygen Evolution Reaction

“…[4] The rate of OERi su sually determined by the fourelectron process which significantly hinders the efficient water splitting. [5,6] An overpotential is neededf or activating the energy barrier. [7] Under ideal conditions, 3.55 kWh electricity is neededt od ecompose al iter of water,w hile 4.26 kWh electricity would be requiredw ith energy loss considered.…”

“…[9] In the past decades, noble metals and their oxidess uch as Ru and RuO 2 are regarded as the state-of-the-art catalysts for OER. [6,9] Nevertheless, the high cost and scarcity limit their widespreadu se. [10,11] Thus, it is essential to develop abundant and low-cost catalystsw ith performance comparable to those of noble metals and noble metal oxides.…”