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Li-rich Mn-based layered oxides with high specific capacity and operating voltages have become one of the most promising materials for lithium-ion batteries (LIBs). However, it still faces several issues of low initial Coulombic efficiency, poor electronic conductivity, and voltage fading due to oxygen release and transition metal rearrangement during cycling. In this study, Li1.2Mn0.54Ni0.13Co0.13O2 (LMR) cathode material with Na ion doping (LMNaR) and CeO2 nanoparticle surface modification (LMNaR@CeO2) is prepared to realize a synergistic modification effect. The doping of Na ions enlarges Li layer spacing to effectively promote the insertion and extraction of lithium ions, which makes the layered structure more stable to reduce the effect of the phase transition. And the CeO2 nanoparticle surface modification restrains the side reactions between electrode and electrolyte, stabilizes lattice oxygen, and eases oxygen release. As a result, LMNaR@CeO2 displays a specific capacity of 196 mAh g–1 after 100 cycles at 0.5 C with a capacity retention of 94% and a merely voltage decay of 0.16 V, which are much better than those of LMR with a specific capacity of 159.6 mAh g–1 and only a 79% capacity retention. Our strategy here provides a feasible approach for the development of Li-rich Mn-based cathode materials for long-lived LIBs. [ABSTRACT FROM AUTHOR]

A local popular Japonica rice (Oryza sating L.) cultivar, Nanjing 9108, was tested with free air controlled enrichment (FACE) approach to study the responses of photosynthetic pigment content and diurnal variation of flag-leaf photosynthesis to elevated atmospheric CO 2 concentration and temperature. Four alternative treatments were designed with two CO 2 concentration levels (ambient and elevated 200 μmol·mol -1 ) and two air temperature regimes (ambient and elevated 1-2 ℃). Diurnal variation of flag-leaf photosynthesis was measured in the middle full stage and the late full stage, and photosynthetic pigment of the leaf was analyzed afterward. Results showed that diurnal variation of net photosynthetic rate (P n ) in each treatment followed a double-peak curve with midday depression feature during late growth stage. Compared to P n under ambient condition, P n under elevated CO 2 concentration increased by 47.6% and 39.1% on average at middle full stage and late full stage, respectively. There was a negative correlation between temperature and P n with no significance. Both elevated CO 2 concentration and temperature had a significant negative effect on stomatal conductance (g s ), decreased by 17.0% and 11.8% on average, respectively. Elevated CO 2 concentration significantly reduced transpiration rate (T r ), chlorophyll a (Chl a), chlorophyll b (Chl b), carotene (Car), total chlorophyll (Chl t) and chlorophyll a/b ratio (Chl a/b) during late growth stage of rice by 5.9%, 50.4%, 21.3%, 41.4%, 39.4% and 21.4% on average, respectively, whereas water use efficiency (WUE) increased by 47.9%. However, there were opposite effects on T r , WUE and photosynthetic pigment content under elevated temperature, with T r increased by 10.2% and WUE decreased by 20.4%. It could be concluded that elevated CO 2 concentration had a greater effect on P n , g s and photosynthetic pigment content of rice leaf than elevated temperature did during late growth stage. Therefore, it should be paid more attention to the colligate effects of elevated CO 2 concentration and high temperature on photosynthesis and photosynthetic pigment content to reduce negative effect of high air temperature.