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Metal–N2 battery can be applied in both energy storage and electrochemical nitrogen reduction reaction (NRR); however, there has been only extraordinarily little study on metal–N2 battery since its electrochemical reversibility still needs further proofs. And its electrochemical performances also need to be enhanced. Herein, we investigated the discharge–charge reactions between Li anode and N2 cathode via designing an efficient catalyst of nanosized SnO2 particles dispersed on N‐doped carbon nanosheets (SnO2@NC) for the Li‐N2 battery, with good cyclic stability and a high specific capacity of 0.25 mA h (~500 mA h g−1) at a large current density of 1000 mA g−1. The electrochemical reversibility of both NRR in the discharge process and nitrogen extraction reaction in the charge process for Li‐N2 battery is discussed. Time‐of‐flight secondary ion mass spectrometry results imply that the SnO2@NC can effectively promote the adsorption of N2 and the activation of NRR in the discharge process. Furthermore, ex situ X‐ray photoelectron spectroscopy and Fourier transform infrared tests are performed to study the electrochemical reversibility of Li‐N2 battery. It can be proved that the formation and decomposition of discharging product Li3N are electrochemical reversible during cycling in our deigned Li‐N2 battery system with SnO2@NC catalyst. [ABSTRACT FROM AUTHOR]

Atmospheric methane (CH4) is an important greenhouse gas that can reflect variations of CH4 emissions and sinks. This study aimed to detect spatial and temporal variations of atmospheric CH4 concentrations in China during 2003–2021 based on CH4 column-averaged dry-air mole fraction (XCH4) products from three satellites, namely, Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY), Greenhouse Gases Observing Satellite (GOSAT), and Copernicus Sentinel-5 Precursor (S5P). The results revealed that XCH4 observed from three satellites showed high agreement in spatiotemporal variations and demonstrated good consistency with ground station measurements. The correlation coefficients (r) between the three satellites were 0.72 and 0.73, and the correlation coefficients for the ground stations were 0.79, 0.66, 0.03, 0.21, 0.70, and 0.80. The spatial distribution of XCH4 in China was generally high in the east and low in the west and close to that of CH4 emissions, indicating that CH4 emission sources dominated the spatial variations of atmospheric XCH4. From 2003 to 2006, XCH4 remained stable with an annual growth rate of 0.51 ppb·yr−1 and then abruptly increased with an overall growth rate of 6.96 ppb·yr−1. There were obvious seasonal changes in XCH4, with peaks in autumn and summer and nadir in winter and spring. These seasonal variations of XCH4 were related to CH4 emissions from rice planting. Rice cultivation areas generally had high XCH4 concentrations, and the growth cycle of rice plants significantly contributed to seasonal variations of XCH4 in the main rice planting areas. These results provide scientific data that could encourage decision-makers to enact policies and processes to reduce methane emissions. [ABSTRACT FROM AUTHOR]