Batteries comprised of LiMn 2 O 4 cathodes (LMO) and Li 4 Ti 5 O 12 anodes (LTO) have potential advantages in terms of cost, safety, and power for transportation applications. In this manuscript, we present results from a cycle and calendar life study of 2 Ah LTO/LMO cells held at temperatures of 30 • C, 45 • C, and 60 • C for 5 months. The cells held at elevated temperatures had measurable loss of capacity and severe loss of power. The LTO anodes harvested from the cells were found to have developed a coating during testing comprised of manganese, phosphorous, and fluorine, which likely resulted in the decreased cycling and power performances. In addition, there was significant gas generation inside of the cells predominantly consisting of hydrogen. We report on the initial diagnostics of the power loss and gas generation for these LTO/LMO cells.

Co-precipitation is a promising method for the synthesis of precursors for lithium ion battery cathodes because it leads to homogeneous composition, narrow particle size distribution, and high packing density materials. Carbonate coprecipitation, as a process to produce transition metal (Mn, Ni, Co) precursors, [1][2][3] has many advantages compared to hydroxide process: First, in the carbonate matrix, the oxidation state of the cations is kept as 2 for all transition metals. Second, the experimental conditions under which carbonates are usually made are less harsh than those of the hydroxide process. Last but not least, carbonate is a tunable process for better morphology control.In this study, the nucleation and growth process of carbonate precursor Ni 0.3 Mn 0.7 CO 3 during coprecipitation reaction in continuous stirred tank reactor (CSTR) was investigated. Theoretical calculations were conducted to optimize pH condition in the carbonate co-precipitation reaction. It was predicted that pH zone range from 7.5 to 8.5 is the optimum pH condition for the carbonate coprecipitation.Evolution of particle size, morphology, composition and structure were characterized as a function of reaction time. It was found that the stoichiometry of the seed particles in the early stage of the reaction was richer in nickel and a small amount of Ni(OH) 2 impurity phase was observed by x-ray diffraction. The carbonate composition stabilized after several hours of co-precipitation. However, continuous growth of the precursor particles lasted for the whole synthesis process with an average particle size around 30 μm. Fig. 1 is the average particle size evolution as a function of reaction time. A linear relationship was observed between the average particle size has and the reaction time. The calculated growth rate was around 1 μm/hour, The collected precursors were washed and dried, then mixed with Li 2 CO 3 to produce the lithiated final materials Li 1.5 (Ni 0.3 Mn 0.7 )O 2+γ . The paper will discuss the relationship between the electrochemical results of the lithiated materials and the physical and morphological properties of the precursors by which those materials were prepared. The submitted manuscript has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory ("Argonne"). Argonne, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357. The U.S. Government retains for itself, and others acting on its behalf, a paid-up nonexclusive, irrevocable worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the Government.

Assemblies formed by solid particles at interfaces have been widely studied because they serve as models of molecular phenomena, including molecular self-assembly. Solid particles adsorbed at interfaces also provide a means of stabilizing liquid-liquid emulsions and synthesizing materials with tunable mechanical, optical, or electronic properties. Whereas many past studies have investigated colloids at interfaces of isotropic liquids, recently, new types of intercolloidal interactions have been unmasked at interfaces of liquid crystals (LCs): The long-range ordering of the LCs, as well as defects within the LCs, mediates intercolloidal interactions with symmetries that differ from those observed with isotropic liquids. Herein, we report the decoration of interfaces formed between aqueous phases and nematic LCs with prescribed densities of solid, micrometer-sized particles. The microparticles assemble into chains with controlled interparticle spacing, consistent with the dipolar symmetry of the defects observed to form about each microparticle. Addition of a molecular surfactant to the aqueous phase results in a continuous ordering transition in the LC, which triggers reorganization of the microparticles, first by increasing the spacing between microparticles within chains and ultimately by forming two-dimensional arrays with local hexagonal symmetry. The ordering transition of the microparticles is reversible and is driven by surfactant-induced changes in the symmetry of the topological defects induced by the microparticles. These results demonstrate that the orderings of solid microparticles and molecular adsorbates are strongly coupled at the interfaces of LCs and that LCs offer the basis of methods for reversible, chemosensitive control of the interfacial organization of solid microparticles. colloidal interactions | interfacial assemblies | liquid crystals | ordering transitionsA liquid crystal (LC) is a phase of matter that blends properties that are typically associated with either crystalline solids or isotropic liquids (1). The molecules that comprise nematic LC phases exhibit long-range orientational order, yet they also possess mobilities characteristic of an isotropic liquid. LCs are most widely known for their use in electrooptic displays; however, they are increasingly being studied in the context of biology, materials science, and analytical chemistry (1). Recently, for example, microdroplets and microparticles dispersed in bulk LCs have been shown to form ordered assemblies, demonstrating that LCs can provide routes to stabilizing emulsions and assembling solid particles into colloidal crystals (2, 3). Although the origins of the interparticle forces that direct the formation of these assemblies in bulk LCs are not yet completely understood, it is clear that the long-range orientational ordering of molecules within the LC phase gives rise to interparticle forces that can be described in terms of the elasticity of the LCs and formation of topological defects within the LC. The LC-mediated interpart...

Interest in developing high performance lithium-ion rechargeable batteries has motivated research in precise control over the composition, phase, and morphology during materials synthesis of battery active material particles.

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