Among the olivine-structured metal phosphate family, LiMnPO{sub 4} exhibits a high discharge potential (4V), which is still compatible with common electrolytes, making it interesting for use in the next generation of Li ion batteries. The extremely low electronic conductivity of this material severely limits its electrochemical performance, however. One strategy to overcome this limitation is to make LiMnPO{sub 4} nanoparticulate to decrease the diffusion distance. Another is to add a carbon or other conductive coating in intimate contact with the nanoparticles of the main phase, as is commonly done with LiFePO{sub 4}. The electrochemical performance of LiFePO{sub 4} is highly dependent on the quality of the carbon coatings on the particles, among other variables. Combustion synthesis allows the co-synthesis of nanoparticles coated with carbon in one step. Hydrothermal synthesis is used industrially to make LiFePO{sub 4} cathode materials and affords a good deal of control over purity, crystallinity, and particle size. A wide range of olivine-structured materials has been successfully prepared by this technique, including LiMnPO{sub 4} in this study. In this paper, we report on the new synthesis of nano-LiMnPO{sub 4} by a combustion method. The purity is dependent upon the conditions used for synthesis, including the type of …

Recently, much research has been directed towards finding a replacement cathode material for LiCoO{sub 2} combining high performance with lower cost and toxicity. One promising candidate material is the mixed transition metal oxide LiNi{sub 0.4}Co{sub 0.2}Mn{sub 0.4}O{sub 2}, which delivers 180 mAh/g below 4.4 V versus Li/Li{sup +}. However, in this material, there is 4% anti-site cation mixing, which hinders the mobility of lithium within the lattice, adversely affecting its rate performance in lithium batteries. Ongoing work in our lab has shown that partial or full substitution of cobalt with aluminum, LiNi{sub 0.4}Co{sub 0.2-y}Al{sub y}Mn{sub 0.4}O{sub 2} (0 < y {le} 0.2), can lead to significant improvements in rate performance. In particular, LiNi{sub 0.4}Co{sub 0.15}Al{sub 0.05}Mn{sub 0.4}O{sub 2} shows greatly improved rate capability with almost no sacrifice in the overall capacity delivered at low rates between 2.0 and 4.3V (Figure 1). The smaller ionic radius of Al{sup 3+} in octahedral coordination (0.535 {angstrom}) compared to Li{sup +} (0.76 {angstrom}) creates a strong driving force for the formation of a more lamellar structure in the aluminum containing materials. XRD experiments and subsequent Rietveld refinement (Figure 2) reveal a significant decrease in anti-site defect concentration upon aluminum substitution, dropping from {approx}4% at …

This article discusses collection development practices to meet the unique characteristics of Web-published materials.