Lithium-Excess Research of Cathode Material Li2MnTiO4 for Lithium-Ion Batteries

Abstract

Lithium-excess and nano-sized Li2+xMn1−x/2TiO4 (x = 0, 0.2, 0.4) cathode materials were synthesized via a sol-gel method. The X-ray diffraction (XRD) experiments indicate that the obtained main phases of Li2.0MnTiO4 and the lithium-excess materials are monoclinic and cubic, respectively. The scanning electron microscope (SEM) images show that the as-prepared particles are well distributed and the primary particles have an average size of about 20-30 nm. The further electrochemical tests reveal that the charge-discharge performance of the material improves remarkably with the lithium content increasing. Particularly, the first discharging capacity at the current of 30 mA g of Li2.4Mn0.8TiO4. In addition, the ex situ XRD experiments indicate that the monoclinic Li2MnTiO4 tends to transform to an amorphous state with the extraction of lithium ions, while the cubic Li2MnTiO4 phase shows better structural reversibility and stability.

Broadening Electromagnetic Absorption Bandwidth: Design from Microscopic Dielectric‐Magnetic Coupled Absorbers to Macroscopic Patterns

“…[41][42][43][44][45][46][47] Moreover, the mechanical properties and the significant factors that impact the performance should be concerned. [48][49][50][51][52][53] Figure 12 displays the effective absorption bandwidth of the materials and structures. As exhibited in Figure 12a, the effective absorption bandwidth of all the samples and designs used in this work has been plotted, which indicates that artificial array structure obviously hold favorable features in achieving broadband absorption.…”

“…Furthermore, alternative methods including using frequency selective radar absorbing materials, graded‐dielectric multilayer, and employment of concise design of the microscopic structures of the fillers are promising methods for achieving high‐performance microwave absorption materials and composites . Moreover, the mechanical properties and the significant factors that impact the performance should be concerned …”

Cation-disordered rocksalt transition metal oxides and oxyfluorides for high energy lithium-ion cathodes

“…1a) and identified Ti-containing oxides as potential DRX candidates due to their low disordering energies. Experimentally, cation-disordered LiTiO 2 has been synthesized 8,25 and a large number of Ti 4+ -containing DRX oxides [43][44][45][46][47][48][49][50][51][52][53][54] have been both successfully synthesized and electrochemically tested in Li-ion cells, with Li 2Àx VTiO 4 exhibiting 4300 mA h g À1 of reversible capacity. 55 Urban's study was later extended to more broadly understand the elements that help stabilize cation disorder at low enough temperature to be synthetically accessible.…”

“…In fact, most Mo 6+ -containing, Nb 5+ -containing and V 5+ -containing DRXs reported to date have average particle sizes ranging from 100 nm to 100 s of nm, as shown in Table 1, and generally require an excess of Li to be percolating. Hydrothermal synthesis, 44,45 soft chemistry approaches, 46 spray-drying methods 47 and sol-gel techniques 49,53,54 have been used to synthesize Ti 4+ -containing DRXs, resulting in smaller particles (o100 nm) and good Li percolation at stoichiometric or even sub-stoichiometric Li contents. A reduced Li content is advantageous as it enables more redox-active M species in the material, resulting in an increase in the transition metal redox…”

Nanostructured Materials for Li-Ion Batteries and Beyond

“…Focusing on the cathode, the nanostructured LiCoPO 4 designed by Manzi and co-workers [ 3 ] illustrated the effect of different Co 2+ sources, solution acidity, and reaction times on the crystal growth of the LiCoPO4 particles by means of a multi-technique approach. Moreover, lithium-excess and nano-sized Li 2+ x Mn 1− x /2 TiO 4 ( x = 0, 0.2, 0.4) cathode materials synthesized via a sol-gel method by Zhang et al [ 4 ] revealed that the charge-discharge performance of the nanostructured material was improved remarkably with increasing lithium content.…”