Understanding Na-ion Storage Mechanism in Na3+xV2-xMx(PO4)3 (M = Ni2+, Co2+, Mg2+; x = 0.1 to 0.5) Cathodes

Bivalent cations (M = Ni2+, Co2+, Mg2+) with different doping contents (x = 0.1, 0.2, 0.3, 0.4, 0.5) were incorporated for vanadium in the Na3+xV2–xMx(PO4)3 (NVP), yielding enhanced rate performanc...