ASIAN JOURNAL OF CHEMISTRY ASIAN JOURNAL OF CHEMISTRY https://doi.org/10.14233/ajchem.2017.20525 INTRODUCTION The development of cathodes for lithium-ion battery has received considerable attention in recent years. Among others, lithium ion battery is used extensively as rechargeable battery [1,2]. For cathode materials studied, LiMn2O4 spinel was consi- dered as a good cathode due to the higher capacity, cycleability and environmentally friendly [3,4]. However, LiMn2O4 electrodes suffers from rapid capacity fade redox during cycling [5,6]. To minimize the capacity fade, replacing Mn 3+ ions by other transition metal ions such as Co, Ni and Cr is one way [7,8]. The presence of cobalt in the structure can improve the capacity retention during cycling by stabilizing the structure [9]. Doping nickel can reduce the lattice parameters and electrical conduc- tivity and increase the capacity of LiMn2O4 [10,11]. Adding chromium can reduce the LiMn2O4 lithium ion composition, stabilize the single phase spinel structure and increase retention capacity upon charging and discharging [12,13]. Many researchers have conducted syntheses of LiMn2O4 with various methods. The synthesis is usually conducted at high temperature to maintain the stability of the spinel phase. Sol-gel, condensing gas and spray pyrolysis methods are believed to retain the phase [14-16]. Problems faced in the synthesis are high cost and not feasable since it was done at high temperature [17,18]. In the present study, we have prepared transition metal-doped LiM0.1Mn1.9O4 (M: Co, Ni, Cr) positive electrodes through reflux and solid-state reaction. Physico-Chemical Properties of LiM 0.10 Mn 1.90 O 4 (M: Co, Ni, Cr) for Potential Cathode Materials DYAH PURWANINGSIH 1,2,* , ROTO ROTO 1 , HARI SUTRISNO 2 and AGUS PURWANTO 3 1 Department of Chemistry, Faculty of Mathematics and Natural Sciences, Gadjah Mada University, Yogyakarta, Indonesia 2 Department of Chemistry Education, Faculty of Mathematics and Natural Sciences, Yogyakarta State University, Yogyakarta, Indonesia 3 Department of Chemical Engineering, Faculty of Engineering, Universitas Sebelas Maret, Surakarta, Indonesia *Corresponding author: Tel: +62 81 327563208; E-mail: dyah_purwaningsih@uny.ac.id Received: 19 January 2017; Accepted: 9 March 2017; Published online: 13 May 2017; AJC-18375 Transition metal-doped spinel cathode materials of LiM0.1Mn1.9O4 (M: Co, Ni, Cr) were prepared by solid-state reaction. The structure and morphology of the products were investigated by X-ray photoelectron spectroscopy, X-ray diffraction, Rietveld refinement and SEM- EDX. The oxidation states of Mn, Co, Ni and Cr were found to be 3+/4+, 2+, 2+ and 3+, respectively as revealed by X-ray photoelectron spectroscopy. SEM-EDX shows uniform particles and the particle size was about 200-700 nm ranges. The diffraction peaks of the prepared solids corresponded to a single phase of cubic spinel structure with a space group Fd3m. Doping of Co, Ni and Cr causes lattice parameters to decrease. The prepared materials have ionic conductivity where LiCo0.10Mn1.90O4 has the highest capacitance. Keywords: Physico-chemical properties, LiM0.10Mn1.90O4, Potential cathode. Asian Journal of Chemistry; Vol. 29, No. 7 (2017), 1466-1470 We mainly focus on analysis of physico-chemical properties of LiM0.1Mn1.9O4 cathodes by X-ray photoelectron microscopic measurement, X-ray diffraction, SEM-EDX and AC impe- dance measurement. EXPERIMENTAL Synthesis of MnO2 and LiMxMn2-xO4: An analytical grade of Mn(CH3COO)2 and Na2S2O8 (Aldrich) were used to prepare MnO2 nanorods by reflux technique. All other chemicals were used without as they were received. In a typical synthesis, Mn(CH3COO)2 and Na2S2O8 were dissolved at room tempe- rature with a molar ratio of 1:1 in 80 mL deionized distilled water by magnetic stirring to form a clear homogeneous solution. The mixed solution was transferred into boiling flask and heated at 120 °C for 12 h. The obtained powder was subse- quently dried at 110 °C for 12 h in air [19]. A typical synthesis of LiM0.10M1.90O4 is as the following. 1 mole of LiOH, 0.10 moles of Co(CH3COO)2 and 1.90 mol of as-synthesized MnO2 were dispersed into high purity ethanol to form a thick slurry, stirred to form fine mixture for several hours and dried at room temperature. The above process was repeated two to three times to produce a well-mixed powder. The LiMn2O4 powder was then ignited at 750 °C for 10 h. The same procedure was used for synthesis LiMn0.10Mn1.90O4, LiNi0.10Mn1.90O4 and LiCr0.10Mn1.90O4 [20,21]. Characterization of LiM0.10Mn1.90O4 microstructure: The cathode material underwent X-ray photoelectron