ACTIVE MATERIAL, ELECTRODE, SECONDARY BATTERY, BATTERY PACK, AND VEHICLE

According to one embodiment, an active material is provided. The active material includes an NbTiOphase and at least one Nb-rich phase selected from the group consisting of an NbTiOphase, an NbTiOphase, and an NbTiOphase. The active material includes potassium and phosphorus, and a total concentration of potassium and phosphorus in the active material is in the range of 0.01% by mass to 5.00% by mass. An average crystallite diameter is in the range of 80 nm to 150 nm. In a particle size distribution chart obtained by a laser diffraction scattering method, D10 is 0.3 μm or greater, and D90 is 10 μm or less. The active material satisfies a peak intensity ratio represented by the following Formula (1). 0