Potassium Cobalt Pyrophosphate as a Nonprecious Bifunctional Electrocatalyst for Zinc–Air Batteries

Abstract

Economic and sustainable (ecological) energy storage forms a major pillar of the global energy sector. Bifunctional electrocatalysts, based on oxygen electrolysis, play a key role in the development of rechargeable metal–air batteries. Pursuing precious metal-free economic catalysts, here, we report K2CoP2O7 pyrophosphate as a robust cathode for secondary zinc–air batteries with efficient oxygen evolution and oxygen reduction (OER||ORR) activity. Prepared by autocombustion, nanoscale K2CoP2O7 exhibited excellent oxygen reduction and evolution reactions among all phosphate-based electrocatalysts. In particular, the OER activity surpassed that of commercial RuO2 with low overpotential (0.27 V). First-principles calculations revealed that the bifunctional activity is rooted in the Co active site with the CoO5 local coordination in the most stable (110) surface. This nanostructured (tetragonal) pyrophosphate can be harnessed as an economic bifunctional catalyst for zinc–air batteries.

Cobalt Anti-MXenes as Promising Anode Materials for Sodium-Ion Batteries

“…While there are several alternatives to LIBs, − sodium-ion batteries (NIBs) have gained considerable attention since sodium is abundant in the earth’s crust (sixth most abundant element). Its resources are distributed nearly equally throughout the world, and it has a lower cost of extraction .…”

Electrochemically Reconstructed Vanadic Oxide-Doped Cobalt Pyrophosphate as an Electrocatalyst for the Oxygen Evolution Reaction

“…As shown in Figure c, the Tafel slope of the V 2 O 5 –Co 2 P 2 O 7 catalyst is 82 mV dec –1 , which is the smallest in comparison to V 2 O 5 + Co 2 P 2 O 7 (228mV dec –1 ), Co 2 P 2 O 7 (330 mV dec –1 ), V 2 O 5 (448 mV dec –1 ), and bare CC (466 mV dec –1 ), revealing the fastest reaction kinetics of the V 2 O 5 –Co 2 P 2 O 7 catalyst. Furthermore, compared to the reported pyrophosphate electrocatalysts (Table S2), the V 2 O 5 –Co 2 P 2 O 7 catalyst exhibits a lower overpotential and moderate Tafel slope (Figure d). − ,,− ,− ,− …”

In situspace-confined growth of Co3O4nanoparticles inside N-doped hollow porous carbon nanospheres as bifunctional oxygen electrocatalysts for high-performance rechargeable zinc–air batteries

“…[20][21][22][23] In particular, introducing heteroatoms into carbon lattices can adjust the local electronic structure and increase the density of active sites, enhancing the catalytic properties of carbon-based materials. [24][25][26] However, the enhanced performance of carbonbased materials, especially for the OER, is still below the benchmark produced by precious metal catalysts, thus dissatisfying the requirement of practicability in the application of RZABs. Transition metal oxide nanomaterials, especially Co 3 O 4 nanoparticles, have high theoretical electrocatalytic activity for the ORR and OER, which can be favorably compared with those of precious metal catalysts.…”