COMPARISON OF 4 V AND 3 V ELECTROCHEMICAL PROPERTIES OF NANOCRYSTALLINE LiMn2O4 CATHODE PARTICLES IN LITHIUM ION BATTERIES PREPARED BY ULTRASONIC SPRAY PYROLYSIS

• Published in: Ceramics international 2014-01, Vol.40 (5), p.7029-7035
• Main Authors: Ebin, B, Battaglia, V, Gurmen, S
• Format: Article
• Language: English
• Subjects: Cathodes; Cathodic dissolution; Cycles; Discharge; Dissolution; Lithium-ion batteries; Morphology; Nanocrystals; Spray pyrolysis
• ISSN: 0272-8842
• DOI: 10.1016/j.ceramint.2013.12.032

Nanocrystalline LiMn2O4 particles were prepared by an ultrasonic spray pyrolysis method using nitrate salts at 800 C in air and the particle structure and morphology were characterised using XRD, SEM, and EDS. In addition, cyclic voltammetry and galvanostatic tests were performed to investigate the effects of structure on the electrochemical behaviour of both the 4 V and 3 V potential plateaus. Particle characterisation showed that the nanocrystalline particles had a spinel structure with submicron size and spherical morphology. Particles, ranging between 75 and 1250 nm, were formed by aggregation of nanoparticles. The discharge capacity of LiMn2O4 particles between 3.0 and 4.5 V was 70 mA h/g and cumulative capacity between 2.2 and 4.5 V was 111 mA h/g at 0.5 C rate. Discharge capacity at the 4 V potential region was reduced to 47% of the initial capacity, whereas cumulative capacity fade was 62% after 100 cycles at 0.5 C rate. Although nanocrystalline LiMn2O4 cathode particles exhibited good rate capability at the 4 V plateau, the capacity decreased rapidly by increasing C- rates and cycling between 2.2 and 4.5 V. The loss of capacity was attributed to phase transformation and the dissolution of the electrode material. Particle characterisation of the used cathodes showed that nanocrystalline LiMn2O4 electrodes partly dissolved during electrochemical cycling.