Nickel Iron Phosphide/Phosphate as an Oxygen Bifunctional Electrocatalyst for High-Power-Density Rechargeable Zn–Air Batteries

Abstract

The evolution of an effective oxygen electrocatalyst is of great importance for the widespread application of Zn–air batteries but remains an immense challenge. Thus, an efficient catalyst toward the oxygen evolution reaction and oxygen reduction reaction (OER and ORR) is highly essential for high-performance Zn–air batteries. Here, we have reported bifunctional nickel iron phosphide/phosphate (NiFeP/Pi) catalysts with various Ni/Fe ratios toward oxygen electrocatalysis in alkaline media. These catalysts are highly active toward OER and ORR, wherein NiFe(1:2)­P/Pi exhibits a low OER overpotential of 0.21 V at 10 mA cm–2 and a high ORR onset potential (0.98 V vs RHE) with the lowest potential difference (ΔE = E 10 – E 1/2) of 0.62 V, which surpasses that of the benchmark Pt/C and RuO2 catalyst as well as those of most previously reported bifunctional catalysts. Furthermore, the NiFe(1:2)­P/Pi-based Zn–air battery demonstrates a very high power density of 395 mW cm–2 and outstanding discharge capacity of 900 mAh g–1@10 mA cm–2 along with steady cyclability, maintaining 98% of the round trip efficiency over 300 cycles. These results are helpful for a good understanding of the composition–activity relation with a certain band gap toward high-performance Zn–air batteries.

Oxygen-Terminated Nb2CO2 MXene with Interfacial Self-Assembled COF as a Bifunctional Catalyst for Durable Zinc–Air Batteries

“…Figure c shows that a Nb 2 CO 2 @COF-based ZAB has a comparable power density of 75 mW cm –2 , which means that ZABs with Nb 2 CO 2 @COF as an air cathode can have competitive energy density. There is still room to improve the capacity as compared with Pt/C + IrO 2 (105 mW cm –2 at 250 mA cm –2 ) . In the discharge test at 5 mA cm –2 , the Nb 2 CO 2 @COF-based battery shows a close specific capacity of 545 and 550 mAh g –1 compared to the Pt/C + IrO 2 -based battery (Figure d).…”

“…There is still room to improve the capacity as compared with Pt/C + IrO 2 (105 mW cm −2 at 250 mA cm −2 ). 47 In the discharge test at 5 mA cm −2 , the Nb 2 CO 2 @COF-based battery shows a close specific capacity of 545 and 550 mAh g −1 compared to the Pt/C + IrO 2 -based battery (Figure 6d). The low-cost advantage of the Nb 2 CO 2 @ COF-based battery is unmatched by precious metals.…”

A multifunctional cobalt iron sulfide electrocatalyst for high performance Zn–air batteries and overall water splitting

“…Recently transition metal-based (Co, Ni, and Fe) synthetic catalysts such as oxides, 8,17 borides, 18,19 sulfides, 20,21 selenides, 22,23 nitrides, 24,25 phosphides, 26–29 etc. have shown remarkable activity towards the ORR, OER, or HER.…”

Novel Fe2.55Sb2alloy nanoparticles incorporated in N-doped carbon as a bifunctional oxygen electrocatalyst for rechargeable Zn–air batteries

“…[13][14][15] Nanocomposites based on non-noble metals (Ni, Co, Fe, Mn, Cu, etc.) [16][17][18][19]55 or metal compounds (oxides, [20][21][22][23] sulfides, [24][25][26][27][28] phosphides, [29][30][31][32] and nitrides [33][34][35] ) incorporated into a N-doped carbon matrix (denoted as M/NC) have shown favorable electrocatalytic activity for both the ORR and OER, which makes them promising for application in Zn-air batteries. As a typical class of electrocatalysts, the catalytic performance of M/NC can be improved by tuning the chemical nature and structure of the metal core (elemental composition, core size, etc.)…”