Boosting Li-O2 Battery Performance via Coupling of P-N Site-Rich N, P Co-Doped Graphene-Like Carbon Nanosheets with Nano-CePO4.

Abstract

Development of efficient and robust cathode catalysts is critical for the commercialization of Li-O2 batteries (LOBs). Herein, a well-designed CePO4 @N-P-CNSs cathode catalyst for LOBs via coupling P-N site-rich N, P co-doped graphene-like carbon nanosheets (N-P-CNSs) with nano-CePO4 via a novel "in situ derivation" coupling strategy by in situ transforming the P atoms of P-C sites in N-P-CNSs to CePO4 is reported. The CePO4 @N-P-CNSs exhibit superior bifunctional ORR/OER activity relative to commercial Pt/C-RuO2 with an overall overpotential of 0.64V (vs RHE). Moreover, the LOB with CePO4 @N-P-CNSs as the cathode catalyst delivers a low charge overpotential of 0.67V (vs Li/Li+ ), high discharge capacity of 29774 mAh g-1 at 100mA g-1 and long cycling stability of 415 cycles, respectively. The remarkably enhanced LOB performance is attributable to the in situ derived CePO4 nanoparticles and the P-N sites in N-P-CNSs, which facilitate increased bifunctional ORR/OER activity, promote the rapid and effective decomposition of Li2 O2 and inhibit the formation of Li2 CO3 . This work may provide new inspiration for designing efficient, durable, and cost-effective cathode catalysts for LOBs.