Highly accessible and stable Co-based active sites enabled by 2D/3D dual-confined strategy for Zn-air batteries

The rational design and facial preparation of highly accessible nanocatalysts that are stable against sintering is a crucial concern in heterogeneous electrocatalysis. Here, an effective and high-stable Co-based heterogeneous electrocatalyst with sufficient exposure of active species was prepared by dual-confined strategy with 3D ZIF-8 frameworks and 2D lamellar poly(ionic liquid) (PIL) networks. As cathode catalyst for Zn-air battery, the as-obtained Co-ZIF8-PIL-800 catalyst displayed excellent oxygen reduction reaction (ORR) performance (E1/2 = 0.87 V), high specific capacity (810.9 mA h·gZn−1) and superior stability than that of Pt/C and RuO2 benchmark. Structure-activity relationship proved that the dispersion of 3D ZIF frameworks in 2D PIL networks ensured the durability of Co-ZIF8-PIL-800, and the confinement of Co species in 2D/3D composite hierarchical frameworks increased the exposure of active sites. The excellent electrocatalytic efficiency of Co-ZIF8-PIL-800 implied the great potential of this 2D/3D dual-confined strategy in constructing highly efficient electrocatalysts.