Rambutan-like Na4MnCr(PO4)3@C/CNTs as a high-energy-density cathode for sodium-ion batteries.

NASICON-type Na 4 MnCr(PO 4) 3 (NMCP) has gained significant attention due to its prominent capacity and voltage platform. However, poor intrinsic electron conductivity severely obstructed its wider application. Here, the NMCP was decorated through structurally integrated with the high conductive carbon nanotubes (CNTs) component via the sol-gel method. The CNTs additive was tightly implanted NMCP bulk, providing fast electron transfer rates, further reduced charge transfer resistance and ohmic resistance, and improving the electrochemical properties of NMCP during the reversible intercalation/deintercalation of Na+. Finally, the as-prepared rambutan-like NMCP/C@CNTs could release a high reversible capability of 118.7 mAh g−1 at 0.1C and exhibit long durability over 500 cycles at a high rate of 10C. The pseudocapacitance contributions were investigated, and the Na storage mechanism was also demonstrated through in-situ synchrotron X-ray diffraction. The assembled NMCP/C@CNTs//HC full cell could deliver a high energy density of 364.4 Wh kg−1. The encouraging electrochemical performance of the full cell will promote the development of sodium ion secondary batteries for large-scale applications in the future. [Display omitted] • Rambutan-like Na 4 MnCr(PO 4) 3 with heterogeneous carbon modified on the surface and inside of particles has been obtained. • The resultant NMCP/C@CNTs with satisfactory structure showed excellent rate capacities. • The NMCP/C@CNTs//HC full batteries delivered high energy density of 364.4 Wh kg−1. [ABSTRACT FROM AUTHOR]