We are grateful for comments to Kewei Hou, Xiaoji Lin and participants at a seminar at the Ohio State University. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research. At least one co-author has disclosed a financial relationship of potential relevance for this research. Further information is available online at http://www.nber.org/papers/w24102.ack NBER working papers are circulated for discussion and comment purposes. They have not been peer-reviewed or been subject to the review by the NBER Board of Directors that accompanies official NBER publications.

Summary TiO2 nanosheets (TiO2NSs) have been investigated for lithium‐sulfur (Li‐S) batteries as strategically designed TiO2 nanosheet/carbon nanotube (TiO2NS/CNT) composite modified polypropylene (PP) separator to inhibit the shuttling of the intermediate polysulfides. The modified separator was fabricated by the vacuum filtration method using the exfoliation TiO2NSs and untreated carbon nanotube (CNT) composites. The multi‐functional TiO2NS/CNT coating not only reduced the electrochemical resistance but also localized the migrating polysulfides by the cooperative effect of physical adsorption and chemical binding. Specifically, the composition ratio of TiO2NSs/CNTs and the interface character have been studied. It was found that the optimum ratio and perfect electrolyte wettability of the TiO2NS/CNT layers were all the critical reasons to achieve good battery performance. The high initial discharge capacity of 1247 mA h g−1 at 0.2 C rate, which was 75% of the theoretical capacity of sulfur, 98% average coulombic efficiency, and 627 mA h g−1 discharge capacity retention after 100 cycles were obtained with the TiO2NS/CNT coating separator.

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Soil microbes are an important component of soil ecosystems that influence material circulation and are involved in the energy flow of ecosystems. The increase in atmospheric nitrogen (N) deposition affects all types of terrestrial ecosystems, including subalpine forests. In general, alpine and high-latitude ecosystems are N limited. Increased N deposition could therefore affect microbial activity and soil respiration. In this study, four levels of N addition, including CK (no N added), N1 (2 g m−2 a−1), N2 (5 g m−2 a−1), and N3 (10 g m−2 a−1), were carried out in a Sichuan redwood forest at the eastern edge of the Tibetan Plateau. The dynamics of soil respiration, major microbial groups, ecoenzymatic stoichiometry, and microbial biomass carbon and nitrogen (MBC and MBN, respectively) were investigated over a year. The results showed that N application significantly increased soil respiration (11%–15%), MBC (5%–9%), MBN (23%–34%), N-acetylglucosidase (56.40%–204.78%), and peroxidase (42.28%–54.87%) activities. The promotion of soil respiration, N-acetylglucosidase, and peroxidase was highest under the N2 treatment. The carbon, nitrogen, and phosphorus metabolism of soil microbes in subalpine forests significantly responded to N application. In the latter stages of N application, microbial metabolism changed from being N restricted to phosphorus restricted, especially under the N2 treatment. Soil bacteria (B) and gram-positive (G+) bacteria were the dominant microbial groups affecting soil respiration. Structural equation modelling indicated that N application significantly promoted soil respiration and microbial biomass, whereas the main microbial groups did not significantly respond to N application. Therefore, we conclude that short-term N addition alleviates microbial nitrogen limitation and promotes soil respiration in the subalpine forest ecosystem that accelerates soil carbon (C) and N cycling. Continuous monitoring is needed to elucidate the underlying mechanisms under long-term N deposition, which may help in forecasting C, N, and P cycling in the alpine region under global climate change.

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