Reversible Electrochemical Insertion/Extraction of Mg and Li Ions for Orthorhombic Mo9Se11with Cluster Structure
Year: 2014
Type: article
Abstract: The reversible electrochemical insertion/extraction of Mg 2+ and Li + into/from a crystalline has been found in orthorhombic Mo 9 Se 11 (o-Mo 9 Se 11 ), the crystal structure of which is composed of molybdenum cluster units. The insertion/extraction reversibility of bivalent ion, Mg 2+ , could be ascribed to improvement of slow diffusion in the host lattice through the delocalization effect of electrons induced by cluster structure as supposed in Chevrel phase. The characteristic of Li/Mg-ion half-cell with o-Mo 9 Se 11 cathode, such as discharge curve and theoretical capacity, are discussed based on the electronic structure. A part of discharge curve in the insertion process of Li + was likely ascribed to the psuedogap structure in the density of state for the electronic band. The reversible capacity of o-Mg x Mo 9 Se 11 was below 40% of the theoretical capacity deduced from the molecular orbital model, whereas over 80% of that was observed in o-Li x Mo 9 Se 11 . The smaller reversible capacity for Mg 2+ could be ascribed to the Coulomb repulsion between bivalent Mg-ions confined in the one-dimensional channel of o-Mo 9 Se 11 , which highly prevents ion-insertion for bivalent Mg-ions compared with that for monovalent Li-ions. We suggest that both delocalized electronic structure and high dimensional ion-channel are necessary to realize reversible cathodes of Mg-ion battery with high capacity.
DOI: 10.1149/2.0941501jes
Authors: Kouji Taniguchi, Takafumi Yoshino, Yunpeng Gu, Yukari Katsura, Hidenori Takagi
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $1,950
OpenAlex ID: W2121451900