Regulating Interfacial Desolvation and Deposition Kinetics Enables Durable Zn Anodes with Ultrahigh Utilization of 80.

Rechargeable aqueous zinc ion batteries (ZIBs) represent a promising technology for large-scale energy storage due to their high capacity, intrinsic safety and low cost. However, Zn anodes suffer from poor reversibility and cycling stability caused by the side-reactions and dendrite issues, which limit the Zn utilization in the ZIBs. Herein, to improve the durability of Zn under high utilization, an aluminum-doped zinc oxide (AZO) interphase is presented. The AZO interphase inhibits side reactions by isolating active Zn from the bulk electrolyte, and enables facile and uniform Zn deposition kinetics by accelerating the desolvation of hydrated Zn2+ and homogenizing the electric field distribution. Accordingly, the AZO-coated Zn (AZO@Zn) anode exhibits a long lifespan of 600 h with Zn utilization of 34.1% at the current density of 10 mA cm-2 . Notably, even under ultrahigh Zn utilization of 80%, the AZO@Zn remains stable cycling over 200 h. Meanwhile, the V2 O5 /AZO@Zn full cell with limited Zn excess displays high capacity retention of 86.8% over 500 cycles at 2 A g-1 . This work provides a simple and efficient strategy to ensure the reversibility and durability of Zn anodes under high utilization conditions, holding a great promise for commercially available ZIBs with competitive energy density.

Molecular-Level Zn-Ion Transfer Pump Specifically Functioning on (002) Facets Enables Durable Zn Anodes.

The modification of metallic Zn anode contributes to solving the cycling issue of Zn-ion batteries (ZIBs) by restraining the dendrite growth and side reactions. In this regard, modulating (002) Zn is an effective way to prolong the lifespan of ZIBs with a parallel arrangement of Zn deposition. Herein, the authors propose to add trace amounts of Zn(BF4 )2 additive in 3 M ZnSO4 to promote in-plane Zn deposition by forming a BF4 - -[Zn(H2 O)6 ]2+ -[Zn(BF4 )3 ]- transfer process and specifically functioning on (002) facets. In this way, the optimized electrolyte highly boosts the cycling stability of Zn anodes with a long lifespan at 34.2% Zn utilization (500 h/10 mA cm-2 ) and 51.3% Zn utilization (360 h/10 mA cm-2 ; 834 h/1 mA cm-2 ). Moreover, the electroplated Zn on Cu substrate exhibits a competitive cumulative plating capacity (CPC) of 2.87 Ah cm-2 under harsh conditions. The assembled Zn|(NH4 )2 V6 O16 ·3H2 O full cells with a high cathode loading of 29.12 mg cm-2 also realizes almost no capacity degradation even after 2000 cycles at 2 A g-1 . With this cost-effective strategy, it is promising to push the development of aqueous ZIBs as well as provide inspiration for metal anode optimization in other energy storage systems.

Puffing ultrathin oxides with nonlayered structures.

Two-dimensional (2D) oxides have unique electrical, optical, magnetic, and catalytic properties, which are promising for a wide range of applications in different fields. However, it is difficult to fabricate most oxides as 2D materials unless they have a layered structure. Here, we present a facile strategy for the synthesis of ultrathin oxide nanosheets using a self-formed sacrificial template of carbon layers by taking advantage of the Maillard reaction and violent redox reaction between glucose and ammonium nitrate. To date, 36 large-area ultrathin oxides (with thickness ranging from ~1.5 to ~4 nm) have been fabricated using this method, including rare-earth oxides, transition metal oxides, III-main group oxides, II-main group oxides, complex perovskite oxides, and high-entropy oxides. In particular, the as-obtained perovskite oxides exhibit great electrocatalytic activity for oxygen evolution reaction in an alkaline solution. This facile, universal, and scalable strategy provides opportunities to study the properties and applications of atomically thin oxide nanomaterials.

LixNa2-xW4O13 nanosheet for scalable electrochromic device.

The printed electronics technology can be used to efficiently construct smart devices and is dependent on functional inks containing well-dispersed active materials. Two-dimensional (2D) materials are promising functional ink candidates due to their superior properties. However, the majority 2D materials can disperse well only in organic solvents or in surfactant-assisted water solutions, which limits their applications. Herein, we report a lithium (Li)-ion exchange method to improve the dispersity of the Na2W4O13 nanosheets in pure water. The Li-ion-exchanged Na2W4O13 (LixNa2-xW4O13) nanosheets show highly stable dispersity in water with a zeta potential of -55 mV. Moreover, this aqueous ink can be sprayed on various substrates to obtain a uniform LixNa2-xW4O13 nanosheet film, exhibiting an excellent electrochromic performance. A complementary electrochromic device containing a LixNa2-xW4O13 nanosheet film as an electrochromic layer and Prussian white (PW) as an ion storage layer exhibits a large optical modulation of 75% at 700 nm, a fast switching response of less than 2 s, and outstanding cyclic stability. This Na2W4O13-based aqueous ink exhibits considerable potential for fabricating large-scale and flexible electrochromic devices, which would meet the practical application requirements.

Analysis of the influence of groundwater on land subsidence in Beijing based on the geographical weighted regression (GWR) model.

A global geological phenomenon caused by natural or human activities is described as land subsidence. Groundwater extraction plays a significant part in causing land subsidence. Due to economic development, urban expansion, and rapid population expansion, the unscientific exploitation of groundwater in Beijing has been accelerated, which makes it the region with the fastest land subsidence rate in China. To study the spatial heterogeneity of land subsidence caused by groundwater aquifers level changes, the monitoring results of land subsidence in 2003-2010 years were analyzed by using PS-InSAR, based on ENVISAT ASAR in Beijing plain area. The maximum value of accumulated land subsidence in the study area is 707 mm, and in this study area multiple subsidence center areas have been formed. A GWR model based on a regular grid has been established by exploring the effects of unconfined aquifer (UA), first confined aquifer (FCA), second confined aquifer (SCA), third confined aquifer (TCA) on land subsidence and their spatial non-stationarity. The change of subsidence in all subsidence areas is positively related to the change of SCA water level. Except the fact that the main control factors of Liyuan and Songzhuang are the change of UA layer, the change of SCA is the main control factor of land subsidence in most subsidence areas. Though the contribution rate of SCA to land subsidence is the highest, the contribution rate of TCA has been increasing. It is predicted that the impact on land subsidence will increase year by year. The results of this will not only help to understand the spatial impact patterns of aquifers on land subsidence zones, but also to formulate optimal groundwater regulation and recharge policies. There is a scarcity of the consideration of the compressible layer in the study and it will become more comprehensive if further datasets are obtained.