New nanocrystalline manganese oxides as cathode materials for lithium batteries: Electron microscopy, electrochemical and X-ray absorption studies

Abstract

New nanostructured manganese oxi-iodides were prepared by redox reaction of sodium permanganate with lithium iodide in aqueous medium at room temperature. Transmission electron microscopy (TEM) showed that they are nanocrystalline with grain size in the 5-10 nm range. TEM and X-ray absorption confirmed the short-range orderded structure of these compounds, which contain octahedrally coordinated manganese atoms. The electrochemical properties were studied as a function of preparation conditions (Li/Mn ratio, carbon incorporation at the synthesis stage and grinding). Best electrochemical results were obtained either on samples with carbon black incorporated directly in the aqueous reaction medium at the synthesis stage, or on samples with carbon mixed after synthesized, submitted to extensive grinding. Typical capacities in the potential window 1.8-3.8 V are160 and 130 mAh/g at the 40th and 100th cycle, respectively.Step-potential electrochemical spectroscopy and the evolution of X-ray absorption spectra on discharge are consistent with a single-phase lithium intercalation reaction with simultaneous manganese oxidation-reduction.

Probing Porous Structure of Single Manganese Oxide Mesorods with Ionic Current

“…Manganese oxide is a popular energy storage material which has been used in lithium ion batteries − as well as in supercapacitors. , It features good capacity, earth abundance, low toxicity, and low cost, and there are numerous methods for synthesizing different types of manganese oxide for use in energy storage devices. While the physical properties, like electrical conductivity and crystal structure, are relatively easy to determine, very little has been done to understand how the porous character of MnO 2 influences transport of lithium and other ions inside and through the material.…”

Manganese, technetium and rhenium

“…45 New nanocrystalline manganese oxides have been prepared for use as cathode materials in lithium batteries by redox reaction of sodium permanganate with lithium iodide in aqueous media at room temperature. 46 The electrochemical properties of the material have also been studied as a function of preparation conditions. Other manganese-containing cathode materials of the form LiMn 2Àx M y O 4 (x = 0, 0.1, 0.2; M = Cr, Co) have been prepared by microwave-induced combustion using lithium, manganese, chromium and cobalt nitrates and urea as starting materials.…”

Amorphous or Nanocrystalline Manganese Oxides for Lithium Battery Cathodes

“…The materials obtained ("MnOx-I") are nanocrystalline with grain size in the 5-10 nm range (see SAED in Figure 2). It yields a single plateau between 1.8 and 4 V with a capacity reaching 150 mAh/g after 40 cycles [4].…”