A bimetallic-activated MnO 2 self-assembly electrode with a dual heterojunction structure for highperformance rechargeable zinc-air batteries (original) (raw)
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Electrochimica Acta, 2012
A composite bifunctional catalyst (MnO 2-NCNT) was prepared from manganese dioxide (MnO 2) nanotubes and nitrogen-doped carbon nanotubes (NCNT) for the purpose of oxygen reduction (ORR) and evolution (OER) catalysis in the rechargeable zinc-air battery. From the half cell test, the MnO 2-NCNT composite illustrated excellent activities towards ORR and OER in alkaline conditions. Based on the battery test, the composite catalyst displayed outstanding discharge and charge performance while maintaining good stability. In both cases, the marked performance improvements from MnO 2-NCNT compared favourably to the NCNT and MnO 2 , which are the constituents of the composite. In particular, MnO 2-NCNT exhibited improved half wave potential by 220 mV compared to MnO 2 and much superior OER stability compared to NCNT based on the rotating ring disk voltammetry results. According to battery test, MnO 2-NCNT decrease the battery resistance by 34% and concurrently improved the durability, discharge and charge performance in comparison to the MnO 2 nanotubes.
Electrochimica Acta, 2016
An efficient, durable and low cost air cathode with low polarization between the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is essential for a high performance and durable secondary zinc-air battery. Different valence states and morphologies of Mn x O y catalysts were synthetized via thermal treatment of EMD (generating Mn 2 O 3 and Mn 3 O 4) and acid digestion of synthetized Mn 2 O 3 (producing a-MnO 2) in order to develop an efficient Bifunctional Air Electrode (BAE). Change in the ratio H + to Mn 2 O 3 during the acid digestion affects the sample microporosity, the crystallographic plane distribution, as well as the physical and chemical adsorbed water which was related to defects, i.e. cation vacancies (Mn 4+) and Mn 3+. These characteristics were discussed and linked to the electrocatalytic activity. The best ORR performing catalyst was that with the higher surface water content (associated to material BET surface area) and a (310) surface as the 2nd more contributing plane (after 211). On the other hand, the catalyst with the higher structural water and with (110) and (200) crystallographic planes being the most intensity contributors (after 211) was the most OER active material. In this work, it was able to find a relationship between catalyst structure and air-efficiency through a volcano-like relationship between air-efficiency and surface water content. Air-efficiency (also take as round-efficiency discharge/charge in battery context) can be taken as a good descriptor of potentially good materials for Zn-Air secondary batteries technology. In this term, we were able to prepare a Bifunctional Air Electrode based on the selected a-MnO 2 sample which demonstrated a roundefficiency of 53%, a DV around 1 V and a neglected loss of the charge potential (about 2.1 V) over the entire lifecycle test (more 200 cycles over 30 hours) with a capacity retention superior to 95%. 2016 Published by Elsevier Ltd.
Nano Energy, 2016
Development of efficient bifunctional electrocatalysts from earth abundant elements, simultaneously active for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), remains to be a grand challenge for electrocatalysis. Herein we firstly synthesized a new type of bifunctional catalyst (NCNT/Co x Mn 1-x O) consisting of non-spinel cobalt-manganese oxide supported on N-doped carbon nanotubes through a simple non-surfactant assistant hydrothermal method. This hybrid catalyst exhibits much higher OER activity than that of IrO 2 , and comparable ORR activity to Pt/C with identical onset potential (0.96 V) in alkaline media. Furthermore, the NCNT/Co x Mn 1-x O catalyst was studied as a cathode in both primary and rechargeable zinc-air batteries demonstrating similar performance to commercial Pt/C or (Pt/C+IrO 2), respectively. Primary zinc-air battery tests show a gravimetric energy density of 695 Wh kg zn-1 , and the rechargeable battery exhibits a high round-trip efficiency evidenced by a low discharge-charge voltage gap (0.57 V) at a current density of 7 mA cm-2 .
Nano-Micro Letters, 2021
Rechargeable zinc-air batteries (ZABs) are currently receiving extensive attention because of their extremely high theoretical specific energy density, low manufacturing costs, and environmental friendliness. Exploring bifunctional catalysts with high activity and stability to overcome sluggish kinetics of oxygen reduction reaction and oxygen evolution reaction is critical for the development of rechargeable ZABs. Atomically dispersed metal-nitrogen-carbon (M-N-C) catalysts possessing prominent advantages of high metal atom utilization and electrocatalytic activity are promising candidates to promote oxygen electrocatalysis. In this work, general principles for designing atomically dispersed M-N-C are reviewed. Then, strategies aiming at enhancing the bifunctional catalytic activity and stability are presented. Finally, the challenges and perspectives of M-N-C bifunctional oxygen catalysts for ZABs are outlined. It is expected that this review will provide insights into the targeted...
Angewandte Chemie (International ed. in English), 2015
The lack of high-efficient, low-cost, and durable bifunctional electrocatalysts that act simultaneously for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) is currently one of the major obstacles to commercializing the electrical rechargeability of zinc-air batteries. A nanocomposite CoO-NiO-NiCo bifunctional electrocatalyst supported by nitrogen-doped multiwall carbon nanotubes (NCNT/CoO-NiO-NiCo) exhibits excellent activity and stability for the ORR/OER in alkaline media. More importantly, real air cathodes made from the bifunctional NCNT/CoO-NiO-NiCo catalysts further demonstrated superior performance to state-of-the-art Pt/C or Pt/C+IrO2 catalysts in primary and rechargeable zinc-air batteries.
MnO2 Heterostructure on Carbon Nanotubes as Cathode Material for Aqueous Zinc-Ion Batteries
International Journal of Molecular Sciences
Due to their cost effectiveness, high safety, and eco-friendliness, zinc-ion batteries (ZIBs) are receiving much attention nowadays. In the production of rechargeable ZIBs, the cathode plays an important role. Manganese oxide (MnO2) is considered the most promising and widely investigated intercalation cathode material. Nonetheless, MnO2 cathodes are subjected to challenging issues viz. limited capacity, low rate capability and poor cycling stability. It is seen that the MnO2 heterostructure can enable long-term cycling stability in different types of energy devices. Herein, a versatile chemical method for the preparation of MnO2 heterostructure on multi-walled carbon nanotubes (MNH-CNT) is reported. Besides, the synthesized MNH-CNT is composed of δ-MnO2 and γ-MnO2. A ZIB using the MNH-CNT cathode delivers a high initial discharge capacity of 236 mAh g−1 at 400 mA g−1, 108 mAh g−1 at 1600 mA g−1 and excellent cycling stability. A pseudocapacitive behavior investigation demonstrates ...
Nanoscale, 2014
A nickel-doped cobalt oxide spinel structure is a promising non-precious metal electrocatalyst for oxygen evolution and oxygen reduction in rechargeable metal-air batteries and water electrolyzers operating with alkaline electrolytes. One dimensional NiCo 2 O 4 (NCO) nanostructures were prepared by using a simple electrospinning technique with two different metal precursors (metal nitrate/PAN and metal acetylacetonate/PAN). The effect of precursor concentration on the morphologies was investigated.
ACS nano, 2016
Rational design of efficient and durable bifunctional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) electrocatalysts is critical for rechargeable metal-air batteries. Here, we developed a facile strategy for fabricating three-dimensional phosphorus and sulfur codoped carbon nitride sponges sandwiched with carbon nanocrystals (P,S-CNS). These materials exhibited high surface area and superior ORR and OER bifunctional catalytic activities than those of Pt/C and RuO2, respectively, concerning its limiting current density and onset potential. Further, we tested the suitability and durability of P,S-CNS as the oxygen cathode for primary and rechargeable Zn-air batteries. The resulting primary Zn-air battery exhibited a high open-circuit voltage of 1.51 V, a high discharge peak power density of 198 mW cm(-2), a specific capacity of 830 mA h g(-1), and better durability for 210 h after mechanical recharging. An extraordinary small charge-discharge voltage polarization...