Highly efficient Li-O2 batteries based on self-standing NiFeP@NC/BC cathode derived from biochar supported Prussian blue analogues

Abstract

Transition metal phosphides (TMPs) are considered as promising electrode materials due to their superior electrical conductivity and excellent redox activity. However, TMPs have rarely been reported as catalysts for lithium air batteries. In the present work, three-dimensional (3D) self-standing NiFeP@NC/BC (BC = biochar) electrode is fabricated by the initial deposition of Prussian blue analogues (PBA) on biomass and the subsequent one-step phosphating process with red phosphorous as the phosphorous source. The as-prepared electrode is directly applied as the cathode for Li-O2 batteries, which delivers good electrochemical performance, such as high specific capacity of 10.9 mAh g−1 cathode at a current density of 0.05 mA cm−2, good rate capability, and long cycle life of >90 cycles. The rational design of this 3D self-standing cathode integrates the advantages of efficient electron transport network of biochar and sufficient accessible reaction sites of TMP catalysts. © 2020