Design of B, P co-doped CoNi bimetallic for boosting supercapacitor performance: Effect of boronation and phosphorization order

The exploration of high-efficiency electrodes is urgent for energy conversion and storage devices. In this work, CoNiBP nanosheets were fabricated by a successive method which is facile and cost-effective. The nanosheet-like structure of CoNiBP enables high exposure of active sites and fast transport of ions and electrons. In addition, the synergistic effect of B and P strengthens the electrochemical performance by tuning the electronic structure of active sites. The CoNiBP electrode exhibits a high specific capacity of 870.8 C g−1 at 1 A g−1 with excellent rate capability and stability. Moreover, the assembled CoNiBP//AC asymmetric supercapacitor (ASC) device delivered an ultrahigh energy density of 71.7 Wh kg−1 at 0.8 kW·kg−1 with good cyclability (∼100% retention of original capacity after 12 000 cycles). With such superior electrochemical performance, CoNiBP is a promising material to be used as electrode in supercapacitors.