The disclosure provides a plurality of particles. Each particle may include a material comprising 0.95 to 1.30 mole fraction Li, at least 0.60 and less than 1.00 mole fraction Co, up to 10,000 ppm Al, 1.90 to 2.10 mole fraction O, and up to 0.30 mole fraction M, where M is at least one element selected from B, Na, Mg, P, Ti, Ca, V, Cr, Fe, Mn, Ni, Cu, Zn, Al, Sc, Y, Ga, Zr, Ru, Mo, La, Si, Nb, Ge, In, Sn, Sb, Te, and Ce. Each particle may also include a surface composition comprising a mixture of LiF and a metal fluoride. An amount of fluorine (F) is greater than 0 and less than or equal to 5000 ppm. The metal fluoride comprises a material selected from the group consisting of AlF3, CaF2, MgF2, and LaF2. The surface composition may also include a metal oxide comprising a material selected from the group consisting of TiO2, MgO, La2O3, CaO, and Al2O3. An amount of the metal oxide is greater than 0 and less than or equal to 20000 ppm.