A Chemical Approach to Raise Cell Voltage and Suppress Phase Transition in O3 Sodium Layered Oxide Electrodes

Sodium ion batteries (NIBs) are one of the versatile technologies for low‐cost rechargeable batteries. O3‐type layered sodium transition metal oxides (NaMO₂, M = transition metal ions) are one of the most promising positive electrode materials considering their capacity. However, the use of O3 phases is limited due to their low redox voltage and associated multiple phase transitions which are detrimental for long cycling. Herein, a simple strategy is proposed to successfully combat these issues. It consists of the introduction of a larger, nontransition metal ion Sn⁴⁺ in NaMO₂ to prepare a series of NaNi_0.5Mn_{0.5? y} Sn _y O₂ (y = 0–0.5) compositions with attractive electrochemical performances, namely for y = 0.5, which shows a single‐phase transition from O3 ? P3 at the very end of the oxidation process. Na‐ion NaNi_0.5Sn_0.5O₂/C coin cells are shown to deliver an average cell voltage of 3.1 V with an excellent capacity retention as compared to an average stepwise voltage of ≈2.8 V and limited capacity retention for the pure NaNi_0.5Mn_0.5O₂ phase_. This study potentially shows the way to manipulate the O3 NaMO₂ for facilitating their practical use in NIBs.     

The crop milk: a potential new route for carotenoid-mediated parental effects

Allocation of carotenoid pigments, either through nutritional provisioning or from endogenous reserves, makes up a form of non-genetic parental investment to progeny that may contribute to fitness. To date, carotenoids derived from endogenous reserves have been acknowledged as important vectors in translating only avian female phenotype and environmental conditions experienced prior to laying. Here, we show that in columbidae, crop milk delivered by both parents may provide chicks with a large amount of endogenous carotenoids at the postzygotic stage. Major carotenoids were xanthophylls and beta-carotene, but their concentrations showed large variation among individuals. Interestingly, a large amount of this variation was explained by brood identity, suggesting either environmental influences and/or phenotypic influences on a parent's ability to transfer these biomolecules. Our study therefore illuminates a potential new route for endogenous carotenoid-mediated parental effects.