Among cobalt-free layered oxides, Li(Ni1-xMnx)O₂ (x ≤0.5) (LNMO) shows high reversible capacity, good cycling performance and thermal stability, and has relatively low cost and toxicity due to the absence of cobalt. In this study, we synthesized LNMO cathode materials having a porous fiber shape with primary particles that had an average diameter of about 328 nm. The prepared LNMO has an increased surface area, on which side reactions between the electrolyte and cathode material occur. Therefore, we coated the conductive polymer PEDOT:PSS to solve the problems that may arise. The coated LNMO exhibited a reversible capacity of 128.03 mAh g-1, and 87.1% capacity retention, at a current density of 0.1 C, for up to 30 cycles. It showed a better performance than uncoated LNMO. The process used in this study can be proposed as a new synthesis method for cobalt-free layered oxide materials.