A high-performance lithium deficient Li_x(Ni_1/3Mn_1/3Co_1/3)O₂ (x<1.0) cathode material with multiphase structure in primary particles has been synthesized by high-temperature sintering of metal hydroxide precursors with lithium carbonate. The metal hydroxide precursors were synthesized by a commercially common spray drying method, and the nanoscale morphology of the hydroxide precursors is translated to the synthesized cathode material during solid state sintering. The synthesized cathode material (hereafter denoted as MPC) were studied for their structure, morphology, and composition. X-ray diffraction pattern and scanning electron microscopy revealed a nanoscale, multiphase, lithium deficient Li_x(Ni_1/3Mn_1/3Co_1/3)O₂ cathode material. Energy dispersive spectroscopy and inductive coupled plasma – optical emission spectroscopy results confirmed the metal ratios and composition. High-resolution transmission electron microscopy and selective area electron diffraction data, from the cross section of the particle after focused ion beam milling, revealed the formation of a layered structure (space group: R-3m) in the core, and a mixed structure consist of spinel (space group: Fd‑3m) and layered structure at the surface. Half cells (2032-type coin cell) made with commercial Li_x(Ni_1/3Mn_1/3Co_1/3)O₂ (x>1.0, Umicore) (hereafter LPC) and MPC showed very high improvement in the rate capability and cycle performance for MPC which is attributed to the high voltage structural stability of the multiphase structure.