Ultrathin porous Mn(PO3)2 nanosheets and MoO2 nanocrystal arrays on N, P-dual-doped graphene for high-energy asymmetric supercapacitors

Recently, heteroatom doped graphene based architectures exhibit promising prospects in the commercial application of supercapacitors because of their higher electrical conductivity and a wider potential window. Herein, we report on ultrathin porous nanosheets Mn(PO3)(2) and MoO2 nanocrystal array on N, P dual-doped graphene (NPG) framework and study their supercapacitor properties. The irregularly overhead Mn(PO3)(2) present a unique structure, which provide clear electron/ion transport channels to accelerate charge transfer together with the three-dimensional NPG structure. The obtained Mn(PO3)(2)/NPG hybrid electrode exhibit an extraordinary specific capacity (2073.4 F g(-1), 1 A g(-1)) and good rate performance (capacity retention rate of 77.8% from 1 A g(-1) to 20 A g(-1)). In addition, the 3D NPG coated with MoO2 nanocrystal have also made a great progress in electrochemical performance of large capacitance and merely 5.54% fading capacitance after 10,000 cycles. Subsequently, the asymmetric supercapacitor (ASC) hybrid devices based on Mn(PO3)(2)/NPG as the positive electrode and MoO2/NPG as the negative electrode has a wide voltage range of 0 similar to 1.8 V, delivers an excellent C-F value of 213.8 F g(-1) and keeps 91.5% initial capacitance retention after 10,000 cycles. Furthermore, the as-prepared ASC also obtains an outstanding energy density of 96.2 W h kg(-1) at a power performance of 726.73 W kg(-1), which demonstrate that the reasonable conductive network of Mn(PO3)(2)/NPG//MoO2/NPG devices can greatly increase the utilization of active substances, improve the performance in all aspects and open up new avenues of the future application and development of supercapacitors.

Automated summary

Heteroatom-doped graphene architectures have shown promising prospects in supercapacitor applications due to their enhanced electrical conductivity and wider potential window. Mn(PO3)(2)/NPG hybrid electrode and MoO2/NPG coating exhibit excellent specific capacity, rate performance, and capacitance retention, providing a new avenue for the development of supercapacitors.