Robust and Highly Active FeNi@NCNT Nanowire Arrays as Integrated Air Electrode for Flexible Solid‐State Rechargeable Zn‐Air Batteries

Abstract

The most challenging issue in flexible/portable energy storage devices, such as metal‐air batteries, is the insufficient electrocatalytic performance of the air‐electrode for oxygen reduction/evolution reactions due to low activity and decomposition of the electrocatalyst from the electrode's surface. In an effort to overcome these barriers, robust and highly active FeNi@NCNTs nanowire arrays are rationally synthesized on carbon cloth which directly serves as an integrated air‐electrode for zinc‐air batteries. FeNi@NCNTs/CC shows excellent bifunctional electrochemical performances toward oxygen reduction reaction (onset potential = 0.95 V, half‐wave potential = 0.77 V vs RHE) and oxygen evolution reaction (η = 252 mV@10 mA cm−2), and exhibits excellent stability after being tested for more than 720 hours. More importantly, flexible solid‐state rechargeable Zn‐air batteries directly equipped with the FeNi@NCNTs/CC air‐cathode are demonstrated to exhibit a high discharge voltage (≈1.0 V@2 mA cm−2) and a low charge voltage (≈1.65 V@2 mA cm−2), along with an excellent mechanical and cycling stability (voltage gap increased ≈0.03 V after 200 cycles). The novel designed air‐cathode and simple methodology for flexible solid‐state rechargeable Zn‐air batteries contribute valuable enlightenment toward the development of emerging portable electronics in practice.

Challenges, mitigation strategies and perspectives in development of zinc-electrode materials and fabrication for rechargeable zinc–air batteries

“…On the contrary, polymer electrolytes have received increasing attention for their application in RZABs. [160][161][162][163][164][165][166][167][168][169][170] It has been shown that the employment of a polymer electrolyte is an effective approach to avoid the flooding of the air-electrode in fluid aqueous systems and mitigate the electrode corrosion because of low convection in the polymer electrolyte, thus enhancing the performance of RZABs. As typical polymer electrolytes, PVA-based polymer…”

Cobalt‐Embedded N‐Doped Carbon Arrays Derived In Situ as Trifunctional Catalyst Toward Hydrogen and Oxygen Evolution, and Oxygen Reduction

“…The half-wave potential of the ORR of the Pt/C is 0.88 V vs RHE, and the OER potential corresponding to the current densities of 10 mA cm À 2 of the RuO 2 is 1.64 V vs RHE in Figure 4a. The above key parameters signify that Co/MMCs exerts excellent OER/ORR electrocatalytic activity which surpasses the vast majority of recently reported bifunctional OER/ ORR electrocatalysts, such as in-situ grown Co 4 N/CNWs with a ΔE value of 0.74 V and J lim of 15 mA cm À 2 , [39] in-situ grown FeNi@NCNTs with a ΔE value of 0.70 V and J lim of 4.7 mA cm À 2 , [56] powder based atomic CoÀ N x À C in hierarchical graphene with a ΔE value of 0.95 V and J lim of 4.75 mA cm À 2 , [57] and powder based Co 2 P/CoN-in-NCNTs with a ΔE value of 0.80 V and J lim of 5.01 mA cm À 2 . [58] Additionally, the OER/ORR performance of Co/MMCs was optimized by regulating the temperature of the final CVD-supported precursor pyrolysis process and different Co contents, as revealed in Supporting Information (SEMs: Figure S5 and S6, OER/ORR/HER electrocatalytic performances: Figure S9 and Figure S10).…”

Recent Advances in Flexible Zinc‐Based Rechargeable Batteries

“…[39,40] This revealed that the rechargeability of Zn-air batteries largely depends on the employment of bifunctional catalysts, excluding the rechargeability of zinc anode. [39,40] This revealed that the rechargeability of Zn-air batteries largely depends on the employment of bifunctional catalysts, excluding the rechargeability of zinc anode.…”