The structural information (including the lattice parameters, atomic sites and coordinates (x, y, z)) of Na2VMn2(PO4)3/C has been presented for the first time. It has a monoclinic lattice with the space group of C2/c and cell parameters of a = 12.0494 Å, b = 12.6198 Å, c = 6.5170 Å, β = 114.7°. The valence states of elements and the vibrational modes of Na2VMn2(PO4)3/C are performed by X-ray photoelectron spectroscopy, Raman and FTIR. Furthermore, at 5 mA g−1, Na2VMn2(PO4)3/C as cathode for SIBs shows a reversible discharge capacity of 80.4 mAh g−1. At 20 mA g−1, Na2VMn2(PO4)3/C shows an initial charge capacity of 46.1 mAh g−1 with the capacity retentions of 63.7% after 100 cycles. The poor cycle stability may be attributed to its low intrinsic Na+ diffusion coefficient (D Na+ ) and Jahn-Teller effect during the sodiation/desodiation process.