Carbonaceous materials with high specific energy capacity are prime candidates for applications in rechargeable lithium batteries. The authors report the synthesis and characterization of ordered mesoporous carbon (CMK‐3), synthesized using ordered silica as a template, with high reversible specific capacity and good charge–discharge cycle characteristics. The performance of CMK‐3 is compared with that of carbon nanotubes, and its superiority is suggested to be related to the three‐dimensional ordered structure of CMK‐3.

A sonochemical method has been successfully used in order to incorporate MnO2 nanoparticles inside the pore channels of CMK‐3 ordered mesoporous carbon. Modification of the intrachannel surfaces of CMK‐3 to make them hydrophilic enables KMnO4 to readily penetrate the pore channels. At the same time, the modification changes the surface reactivity, enabling the formation of MnO2 nanoparticles inside the pores of CMK‐3 by the sonochemical reduction of metal ions. The resultant structures were characterized by X‐ray diffraction (XRD), nitrogen adsorption, and transmission electron microscopy (TEM). CMK‐3 with 20 wt.‐% loading of MnO2 inside CMK‐3 delivered an improved discharge performance of 223 mA h g–1 at a relatively high rate of 1 A g–1. Almost no decrease in specific capacity is observed for the second cycle, and a discharge capacity of more than 165 mA h g–1 is retained after 100 cycles. This is attributed to the nanometer‐sized MnO2 formed inside CMK‐3 and the high surface area of the mesopores (3.1 nm) in which the MnO2 nanoparticles are formed.

Fine single-domain and polydomain particles of tetragonal ZrO, were prepared by hydrothermal and heat treatment of ZrO,.nNO. The particles were characterized by X-ray diffraction, electron microscopy, NMR, mass spectrometry, and ir spectroscopy. The main impurity in the samples was 1 to 2 wt% OH-ions, most of which were concentrated on the particle surfaces or a t domain boundaries; some were also distributed in the lattice. Fine single-domain tetragonal particles were strain-free, but polydomain particles had large strains. The single-domain tetragonal particles were transformed much more easily than the polydomain particles by mechanical treatment. The stablization of metastable tetragonal ZrOI cannot be explained adequately by the surfaceenergy theory. An explanation based on the concept of a martensitic transformation may be more reasonable.

By means of annealing LaBaCo 2 O 5 under high pressure oxygen, we have successfully synthesized a new A-site ordered perovskite cobaltite, LaBaCo 2 O 6 . The structure and electromagnetic properties of LaBaCo 2 O 6 have been investigated and compared to those of the ordinary A-site disordered La 0:5 Ba 0:5 -CoO 3 . Both LaBaCo 2 O 6 and La 0:5 Ba 0:5 CoO 3 have mixed states of low-spin and intermediate-spin states and show metallic behaviors generated by double exchange interaction. LaBaCo 2 O 6 has a ferromagnetic transition at T C ¼ 175 K, which is lower by 15 K than T C of La 0:5 Ba 0:5 CoO 3 . At around 140 K, some structural changes are observed in both compounds and below the temperature they exhibit magnetic glassy (cluster glass) behaviors, accompanied by the gradual change to insulating or simiconductive behaviors. The refined structural data and magnetic and electrical properties suggest a partial d x 2 Ày 2 orbital ordering for LaBaCo 2 O 6 below 140 K, in contrast to a partial d 3z 2 Àr 2 orbital ordering for La 0:5 Ba 0:5 CoO 3 .