Facile and Cost Effective Synthesized Mesoporous Spinel NiCo₂O₄as Catalyst for Non-Aqueous Lithium-Oxygen Batteries

Abstract

The electrochemical performance of lithium-oxygen batteries can be significantly improved by employing a suitable catalyst to enhance the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Herein, a versatile, effective and economic co-precipitation synthesis of spinel NiCo 2 O 4 with an urchin-like structure has been reported as an electrocatalyst for rechargeable non-aqueous Li-O 2 batteries. The spherical urchin-like structure of spinel NiCo 2 O 4 was formed without the use of any template or surfactant. The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) kinetics in the Li-O 2 batteries could be drastically improved by employing the effective NiCo 2 O 4 catalyst, achieving a higher discharge potential and rate. In particular, the urchin-like structure of the catalyst not only provides more electrocatalytic sites but also promotes mass transport in the electrolyte. In addition, mesoporous NiCo 2 O 4 can efficiently catalyze the formation and decomposition of Li 2 O 2 . The Li-O 2 battery containing the urchin-like NiCo 2 O 4 catalyst exhibited the highest specific capacity of about 7309 mA h g −1 at 0.2 mA cm −2 . The integrity and porosity of spinel NiCo 2 O 4 had a significant effect on the performance of the Li-O 2 battery with reasonable specific capacity and cyclability, suggesting that the NiCo 2 O 4 -based materials can be effective catalysts for oxygen electrode in high performance Li-O 2 batteries.Recently, Li-ion batteries (LIBs) have been the main energy storage media for portable electronic devices and electric vehicles/hybrid electric vehicles (EV/HEV). Unfortunately, the current LIBs can store only a limited amount of energy and are still relatively expensive. 1,2 In particular, to overcome the disadvantage of the insufficient energy density of LIB, a new battery chemistry with a higher energy density is needed. Recently, lithium-oxygen (Li-O 2 ) batteries have attracted much attention as a promising alternative to LIB for next generation electric vehicles, owing to their large theoretical energy density. 1,3-6 Among various types of Li-O 2 batteries, the non-aqueous system has achieved more encouraging results than other counterparts. 7,8 However, the stability and rate capability of the Li-O 2 battery need to be improved further for its commercialization. 5,9 The typical Li-O 2 cell consists of a porous oxygen electrode for the permeation of oxygen, an electrolyte containing a dissolved lithium salt, and a lithium metal electrode, which can greatly affect the capacity and durability of the cell. 10,11 In particular, the oxygen electrode and lithium electrode plays a crucial role in achieving high capacity and durability for the Li-O 2 battery and represent most serious challenge for the development of the battery. 6,12 Moreover, the large overpotential of the Li-O 2 battery is mainly attributed to the sluggish kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) on the oxygen electrode. In addition, the rechargeability of the ...

Simple synthesis of highly catalytic carbon-free MnCo2O4@Ni as an oxygen electrode for rechargeable Li–O2 batteries with long-term stability

“…Interestingly, FSMCO displayed superior ORR activities, not only in specific capacities but also in plateau potentials compared to KB-MCO catalysts. Moreover, the charge-discharge potential gap of about 0.65 V observed at 100 mA·g −1 was comparable to that reported for precious metal based catalysts such as Au/C, Pt/C 27 , Au/Pt nanoparticles 28 29 and Ru-graphene 30 , and lower than that for other reported catalysts such as carbonous materials 31 32 33 , metal oxides and their carbonous composites 13 14 15 16 17 18 19 20 21 34 35 , pyrochlore 36 , MnCo 2 O 4 -graphene 22 and mesoporous MnCo 2 O 4 37 at a comparable applied current in similar ether based electrolytes.…”

“…Transition metal oxides such as Co and Mn oxides have also been considered as potential candidate electrocatalysts for bi-functional oxygen electrodes due to their high catalytic activity and good corrosion stability for Li-O 2 batteries 13 14 15 16 . Among various types of metal oxides, mixed transition metal oxides with a spinel structure are of interest as an electrocatalyst for ORR and OER due to their low cost, good stability, high activity, low toxicity, and simple preparation 17 18 19 20 . It is well known that the spinel compounds with general formula AB 2 O 4 (A,B = Metal) are built around a closely packed array of O 2 − ions, with A 2+ and B 3+ cations occupying part or all of the tetrahedral and octahedral sites, respectively.…”

Rechargeable Photoactive Zn‐Air Batteries Using NiCo2S4 as an Efficient Bifunctional Photocatalyst towards OER/ORR at the Cathode

“…100 folds, which is significant for excellent electrochemical performance . Furthermore, due to the lower electronegativity and larger atomic radius of sulfur as compared to oxygen, the NiCo 2 S 4 (NCS) exhibits a more flexible structure, richer redox properties, and suitable band structure over NiCo 2 O 4 . Based on all these properties, a spinel metal sulfide could be ideal as a photoactive bifunctional OER and ORR catalyst.…”

Defective NiFe2O4 Nanoparticles for Efficient Urea Electro‐oxidation

“…Synthesis of NFO nanoparticles:N FO nanoparticles were synthesized by coprecipitation method. [57] In detail, 10 mmol ferric nitrate (Fe(NO 3 ) 3 ·9 H 2 O, 99.95 %, Sigma Aldrich), 5mmol nickel nitrate (Ni(NO 3 ) 2 ·6 H 2 O, 99.99 %, Sigma Aldrich) and 100 mmol urea (99.5 %, Sigma Aldrich) were solved and mixed in 100 mL deionized water. The solution was kept at 90 8Cf or 10 hours in an oven.…”