When the current rate was restored

When the current rate was restored to 100mAg−1, the reversible capacities still returned to 744.4mAh g−1, implying a remarkable structural stability during the fast charge/discharge processes. As a comparison, the NPHC-1 and NHC displayed low specific capacities of 50.2 and 72.2mAh g−1 under a high current density of 8.0Ag−1, obviously inferior than that of NPHC. In addition, the storage capacity of NHC decayed fast with the scan rate increasing, implying the P functionalization enhanced the electrical conductivity, contributed the pseudo-capacitance and hence increased the specific capacity and rate performance. As expected, the NPHC electrodes (Fig. 4C) showed the highest reversible capacity of 368.3mAhg−1at 1000 mAg−1 after 500 cycles, followed by NHC electrodes (206.4mAhg−1) and NPHC-1 electrodes (153.1mAhg−1). It was thus concluded that the defect with less confinement from template and a properly controlled amount of phosphorous additive optimized the electrochemical performance of hard carbons. The high-rate long term cycling performances of NPHC at 2000mAg−1 were measured after an activating process, showed inFig. 4D. It exhibited a reversible capacity of 256.7mAh g−1 after 1000 cycles with the retention of 83% relative to that of the tenth cycle. The NPHCanodematerialswithspecialstructure andcompositionexhibited a superior rate performance than commercial graphite (CG) anode (Fig. S5a) and previous reported carbonaceous anodes for LIBs (Table S3). The CG anode showed low capacity of 311.3mAh g−1 at 50mAg−1, and poor rate capability (164.7mAh g−1 at 200mAg−1), which severely limited its wide application. The excellent Li-storage performance of NPHC could be attributed to its larger surface area, higher N, P, O-containing, more defect sites, and hierarchically porous architecture for more Li+ storage and insertion sites [38]. The pure NPHC (Fig.S5b)withoutaddingacetyleneblackshowedhighspecificcapacity (749.7mAh g−1) at 50mAg −1, nonetheless, poor rate capability, so, the additive acetylene black would greatly improve the rate performance and cycling stability.