LiMn2O4-based spinels have been extensively studied as positive electrode materials for lithium-ion batteries. Our investigations have shown that, by using the Pechini process, the performance of these materials can be improved significantly through adjustments to the synthesis conditions and composition by means of selective doping. This paper reports the results of neutron and ex situ X-ray diffraction studies performed to examine the structural changes that occur during lithium ion insertion into various LiMn,O4 compositions. It appears that an ordering intercalation of lithium ions occurs in the lithium concentration range of 0.15-0.35, followed by a second-order phase transformation when the lithium population is close to 0.5, leading to a random lithium insertion into a single-spinel phase from x = 0.5 to 1.0. * Electrochemical Society Student Member. * * Electrochemical Society Active Member.agreement with many literature reports,4"°13 including results obtained from the ionic modeling of various lithium manganese spinel compounds.'3 However, the reason is not cleat One goal of this study was to explore the intrin-

Antibodies to PF4/heparin can be demonstrated in almost all patients with heparin-induced thrombocytopenia/thrombosis (HIT/HITT) and in some persons exposed to heparin who do not have clinical manifestations. The role of anti-PF4/heparin antibodies in the pathogenesis of HIT/HITT has been difficult to establish because the antibodies found in serum are generally polyclonal and polyspecific. To circumvent this problem, we developed a murine monoclonal antibody (mAb) to human (h) PF4/heparin complexes. A monoclonal IgG2bκ antibody (designated KKO) was identified that bound specifically to hPF4/heparin complexes. Maximal binding of KKO to hPF4/heparin complexes occurred at similar molar ratios of PF4:heparin observed for HIT/HITT antibodies. KKO also bound to hPF4 in association with other glycosaminoglycans. Platelet activation by KKO required heparin and was abrogated by blockade of FcγRIIA. In the presence of PF4, KKO bound to endothelial cells, but not to CHO cells lacking heparan sulfate proteoglycans. Variants of PF4 complexed to heparin were recognized equally well by KKO and HIT/HITT sera. KKO competes for binding with a subset of HIT/HITT antibodies that are relatively spared by mutations in the 3rd domain of PF4. The nucleotide and predicted amino acid sequences of KKO and RTO, a murine anti-hPF4 mAb that does not require heparin for binding, revealed no obvious relationship in either the heavy- or the light-chain immunoglobulin variable regions. These studies suggest that KKO recapitulates the antigenic and functional specificity of a subset of HIT/HITT antibodies and may, therefore, provide insight into the pathogenesis of thrombocytopenia and thrombosis in affected persons.

LiMn2O4 ‐based spinels are of great interest as positive electrode materials for lithium‐ion batteries. We describe here what is believed to be the first synthesis of these materials using the Pechini process, a low temperature synthetic method that often yields inorganic oxides of excellent phase purity and well‐controlled stoichiometry. Using this process, it has been possible to synthesize phase‐pure crystalline spinel LiMn2O4 by calcining the appropriate polymeric precursors in air at 250°C for several hours. The influence of different firing temperatures and the effect of substituting a small amount of Mn with Ni have also been explored. Electrochemical studies show that the Pechini‐synthesized materials appear to offer not only high quality performance but also significant analytical advantages which allow us to understand the structural mechanism of Li intercalation.