Jiage Zhao

P2-type Na2/3Fe1/3Mn2/3O2 was prepared by means of solid-state reaction. Its electrochemical properties as a cathode for sodium-ion batteries were investigated in the 1.5-4.3 V range vs. Na metal. This material delivers an initial discharge capacity as high as 193 mAh/g and maintains 153 mAh/g in 40 cycles. Such a high reversible capacity is achieved because both Mn3+/Mn4+ and Fe3+/ Fe4+ become active in the studied voltage range, as confirmed by X-ray absorption spectroscopy. The thermal stability of charged cathodes was investigated by differential scanning calorimetry. Although the total heat generated by the fully charged Na0.25Fe1/3Mn 2/3O2 is larger than that of the Li0.5CoO 2 used as a reference, it is remarkably stable up to ca. 320 °C. © Published by Elsevier B.V.

© 2015, Springer-Verlag Berlin Heidelberg.We study an information aggregation game in which each of a finite collection of “senders” receives a private signal and submits a report to the center, who then makes a decision based on the average of these reports. The integration of three features distinguishes our framework from the related literature: players’ reports are aggregated by a mechanistic averaging rule, their strategy sets are intervals rather than binary choices, and they are ex ante heterogeneous. In this setting, players engage in a “tug-of-war,” as they exaggerate and counter-exaggerate in order to manipulate the center’s decision. While incentives to exaggerate have been studied extensively, the phenomenon of counter-exaggeration is less well understood. Our main results are as follows. First, the cycle of counter-exaggeration can be broken only by the imposition of exogenous bounds on the space of admissible sender reports. Second, in the unique pure-strategy equilibrium, all but at most one player is constrained with positive probability by one of the report bounds. Our third and fourth results hold for a class of “anchored” games. We show that if the report space is strictly contained in the signal space, then welfare is increasing in the size of the report space, but if the containment relation is reversed, welfare is independent of the size of the space. Finally, the equilibrium performance of our heterogeneous players can be unambiguously ranked: a player’s equilibrium payoff is inversely related to the probability that her exaggeration will be thwarted by the report bounds.