A high performance electrode material for lithium ion batteries derived from a cobalt-based coordination polymer

Abstract

A carbon rich coordination polymer, [Co(fa)(bpy)] n (1), based on formic acid (fa) and an auxiliary ligand 4,4`-bipyridine (bpy) is utilized as a single source precursor to an exceptional lithium-ion battery electrode material. Compound 1 consists of cobalt-formate chains connected via bipyridine ligands into a three dimensional lattice. A cobalt-oxide/carbon composite material is obtained by the controlled carbonization of 1 at 900 °C. Morphological, structural, and chemical analysis of the composite is carried out with HR-TEM, XPS and PXRD techniques. This new composite material demonstrates a high specific capacity of 1080 mAhg-1 , a coulombic efficiency of 94%, and a stable cyclic retention for upto 30 cycles. The electrochemical properties of this new material are discussed in relation to the structural and chemical characteristics of precursor dependence of the carbonized hybrid nanomaterial.

Constructing a Cr-Substituted Co-Free Li-Rich Ternary Cathode with a Spinel-Layered Biphase Interface

“…Garnering considerable attention under the predicament of energy crisis, the lithium-ion batteries (LIBs), which are applied in electric vehicles and portable electronics, imperatively require to achieve a high energy density. − One of the most crucial points of enhancing the energy density of LIBs is how to develop the favorable cathode materials with a higher specific capacity and work voltage. − Currently, lithium-rich manganese-based layered oxides (LRMOs) have emerged from diverse amounts of traditional cathode materials due to their high working voltage and specific capacity (>250 mAh g –1 ). − In addition, it has been well identified that the remarkable capacity of LRMOs arises from the synergistic effect of anions and cations in hybrid redox reactions, which delivers the compensatory extra charge/ion exchange. , Simultaneously, the redox of anions (e.g., oxygen) during cycling also makes an adverse difference, namely, voltage decay, which impedes their wide-scale commercial application. Cobalt, which is one of the most important elements within ternary cathode materials, has been broadly regarded as a contributor to stabilizing the material structure and optimizing the cycling and rate performance.…”