Synthesis and characterization of integrated layered nanocomposites for lithium ion batteries
- PDF / 1,570,612 Bytes
- 9 Pages / 595.28 x 793.7 pts Page_size
- 86 Downloads / 200 Views
NANO EXPRESS
Open Access
Synthesis and characterization of integrated layered nanocomposites for lithium ion batteries Jihyeon Gim, Jinju Song, Hyosun Park, Jungwon Kang, Kangkun Kim, Vinod Mathew and Jaekook Kim*
Abstract The series of Li[NixMxLi1/3-xMn2/3-x]O2 cathodes, where M is cobalt or chromium with a wide compositional range x from 0 to 0.33, were prepared by hydroxide coprecipitation method with subsequent quenching. The sample structures were investigated using X-ray diffraction results which were indexed completely on the basis of a ¯ with monoclinic C2/m phase as expected. The morphologies and trigonal structure of space group R3m electrochemical properties of the samples obtained were compared as the value of x and substituted transition metal. The particle sizes of cobalt-substituted Li[NixCoxLi1/3-xMn2/3-x]O2 samples are much smaller than those of the Li[NixCrxLi1/3-xMn2/3-x]O2 system. The electrode containing Li[NixCoxLi1/3-xMn2/3-x]O2 with x = 0.10 delivered a discharge capacity of above 200 mAh/g after 10 cycles due to the activation of Li2MnO3. PACS: 82.47.Aa; 82.47.-a; 82.45.Fk. Keywords: lithium ion batteries, cathodes, nanocomposites, coprecipitation
Introduction The development of rechargeable lithium ion batteries depends critically on the technological advances in electrode materials. Over the years, several compounds such as spinel LiMn 2 O 4 , olivine LiFePO 4 [1], and layered LiCoO 2 and LiNiO 2 have been studied extensively by many researchers as cathode materials for lithium ion batteries. In fact, LiMn 2O4 and LiFePO4 have distinct advantages of being cost-effective and environmentally benign. However, LiMn2O4 suffers from capacity fading due to the dissolution of manganese and Jahn-Teller distortion [2,3], while LiFePO4 delivers insufficient capacity and low electronic conductivity [4]. Commercially used LiCoO2 cathode has advantages of easy synthesis and excellent lithium ion mobility though challenging issues of stability, achieving practical capacities, and environmental risks need to be addressed [2]. ¯ ) The layer-structured rhombohedral LiMnO 2 ( R3m attracts interest as a potential cathode due to its cost effectiveness and relatively high capacity, but it exhibits severe capacity fading during extended cycling. More precisely, its discharge behavior during electrochemical cycling needs significant improvement. The strategies to * Correspondence: [email protected] Department of Materials Science and Engineering, Chonnam National University, 300 Yongbongdong, Bukgu, Gwangju, 500-757, South Korea
overcome such limitations in rhombohedral LiMnO 2 have been focused on metal ion substitution [5,6]. Due to its higher theoretical capacity, LiNiO2 has also been investigated as an alternative cathode to commercial LiCoO 2 . However, it is complicated to synthesize a pure-layered structure with a well-ordered phase because of severe cationic disordering between nickel and lithium ions that occurs due to the ionic radii values of Ni 2+ (0.069 nm) and Li + (0.068 nm) being almost
Data Loading...
