Single-layer fuel cells (SLFCs) based on mixed semiconductors and ionic conductors demonstrate  simplified material preparation and fabrication procedure and possess high performance potentially. However, the operational stability and principle of SLFCs have not yet been convinced of either commercialization or fundamental interests. We hereby report on the employment of a perovskite oxide-based phase-structured redox-stable semiconductor prior to determining a possible solution that improves the durability of the SLFC. Feasible working principles are established and an in-depth understanding of the short-circuit-free phenomenon in SLFCs with the mixed ionic and electronic conductors is provided. Additionally, a smart material design and cell structure processing are also proposed. An extended nonstop testing period of up to 2 days confirms the project feasibility and improved durability of the SLFCs, achieved by replacing the unstable lithiated oxide phase with redox-stable perovskite oxide, though the electrochemical performance is sacrificed. The precipitated metal/alloy nanoparticle on perovskite oxide not only improves the electrode reaction kinetics but also facilitates the charge separation and ionic conduction in SLFCs, consequently enhancing the fuel cell performance and electrical efficiency. The results confirmed the potential of stable operation for future practical deployment of SLFCs via appropriate selection of material and cell structure design. It is greatly believed that the physical junction plays a crucial role in overcoming the internal short-circuit issue of SLFCs.

No abstract

No abstract

Exploring the changes of ecosystem services value caused by land use transformation driven by urbanization is crucial for ensuring the safety of the regional ecological environment and for enhancing the value of ecosystem services. Based on the land use remote sensing data during the rapid urbanization development period of Hubei Province from 1995 to 2015, this study analyzed the characteristics of land use/land cover change and land use transformation. The spatial–temporal response characteristics and evolution of ecosystem services value (ESV) to land use transformation driven by urbanization were measured by equivalent factor method, spatial autocorrelation analysis, hot spot analysis and gravity model. We found that: (1) Driven by urbanization, the most significant feature of land use transformation in Hubei Province was the expansion of the built-up land and the significant reduction of cropland and forest, among which 90% of the new built-up land was converted from cropland and forest. (2) This land use transformation became the main source of ESV losses. Especially, the sharp increase of the built-up land from 2010 to 2015, occupying cropland and forest, resulted in ESV losses of nearly USD 320 million. The service capacity of climate regulation, soil conservation, gas regulation and food production undertaken by cropland and forest decreased. (3) The ecosystem services value in the study area showed spatial distribution characteristics of high in the west and low in the middle and east regions. The center of gravity of ESV shifted from northwest to southeast. Due to the sharp increase of the built-up land from 2010 to 2015, the center of gravity shift rebounded. This study can help policymakers better understand the trade−offs between land use transformation and ecosystem services driven by urbanization.

No abstract