A Web-like Three-dimensional Binder for Silicon Anode in Lithium-ion Batteries

Si anode is of paramount importance for advanced energy-dense lithium-ion batteries(LIBs).However,the large volume change as well as stress generates during its lithiation-delithiation process poses a great challenge to the long-term cycling and hindering its application.Herein this work,a composite binder is prepared with a soft component,guar gum(GG),and a rigid linear polymer,anionic polyacrylamide(APAM).Rich hydroxy,carboxyl,and amide groups on the polymer chains not only enable intermolecular crosslinking to form a web-like binder,A2G1,but also realize strong chemical binding as well as physical encapsulating to Si particles.The resultant electrode shows limited thickness change of merely 9%on lithiation and almost recovers its original thickness on delithiation.It demonstrates high reversible capacity of 2104.3 mAh g^(-1)after 100 cycles at a current density of 1800 mA g^(-1),and in constant capacity(1000 mAh g^(-1))test,it also shows a long life of 392 cycles.Therefore,this soft-hard combining web-like binder illustrates its great potential in the future applications.

Changes in macular thickness following glaucoma surgery

Dear Sir,Previous reports have illustrated reversible structural changes in optic disc cupping,the lamina cribrosa,and the retinal nerve fiber layer(RNFL)following glaucoma surgery[1-3].However,few studies have assessed changes in macular thickness following such intervention.Our aim was to investigate the impact of intraocular pressure(IOP)reduction after glaucoma surgery on total macular thickness

High-precision measurements of the inter-annual evolution for Urumqi Glacier No.1 in eastern Tien Shan,China

High-precision measuring of glacier evolution remains a challenge as the available global and regional remote sensing techniques cannot satisfactorily capture the local-scale processes of most small-and medium-sized mountain glaciers.In this study,we use a high-precision local remote sensing technique,long-range terrestrial laser scanning(TLS),to measure the evolution of Urumqi Glacier No.1 at an annual scale.We found that the dense point clouds derived from the TLS survey can be used to reconstruct glacier surface terrain,with certain details,such as depressions,debris-covered areas,and supra-glacial drainages can be distinguished.The glacier experienced pronounced thickness thinning and continuous retreat over the last four mass-balance years(2015−2019).The mean surface slope of Urumqi Glacier No.1 gradually steepened,which may increase the removal of glacier mass.The glacier was deeply incised by two very prominent primary supra-glacial rivers,and those rivers presented a widening trend.Extensive networks of supra-glacial channels had a significant impact on accelerated glacier mass loss.High-precision measuring is of vital importance to understanding the annual evolution of this type of glacier.

Inventory and Geometrical Changes in Small Glaciers Covering Three Northern Patagonian Summits Using Remote Sensing and GIS Techniques

In the last few decades, a large quantity of research has been performed to elucidate the current behavior of glaciers in southern Chile, especially with respect to the volumetric changes in the outlets of the Northern and Southern Patagonian Icefields （NPI and SPI, respectively）. Calculations have shown a generalized thinning and withdrawal, which greatly contributes to the increase in sea level attributed to the ice melt from non-polar glaciers. However, these icefields are surrounded by many small icecaps, which have＇yet to be studied in detail. A precise estimation of the volume of ice located in these mountain chains could provide new information with respect to this area＇s exact contribution to the increase in sea level. Thus, this study presents an inventory of relatively small Northern Patagonian glaciers in the surrounding of the three summits： Mount Queulat, and the Maca and Hudson volcanoes. The study used remote sensing techniques in a GIS environment to determine the margins, surface areas, thickness changes and hypsometry for the glaciated zones. Landsat images from different dates were analyzed using standard band ratio and screen delineation techniques. Additionally, digital elevation models from different dates were compared using map algebra, calculating thickness changes. Based on the results, we propose that there are important volumetric changes in the glaciers studied, whichcould be explained by precipitation trends in a general context, and an influence of the glaciers＇ sizes in some local response. Therefore, we suggest the exact contribution of the Patagonia to the increase in sea level corresponds to a regional pattern rather than just the behavior of a single ice field.

Thickness evolution of commercial Li-ion pouch cells with siliconbased composite anodes and NCA cathodes

It is significant to monitor the thickness change of commercial Li-ion pouch cells that are assembled from Si-based electrodes and layered cathodes since the volume variation is critically linked with kinetic reaction mechanism and chemomechanical degradation. In this work, the single-point and full-field measurements are conducted on the thickness evolution of Si Ox/Cgraphite/lithium nickel-cobalt-aluminum oxide(Si Ox-G/NCA) batteries. It is found that an abnormal overshoot that has been rarely observed in the previous studies appears at the beginning of discharge, which is believed to be the combined results between the rapid expansion of NCA and the contraction of graphite related to the state of charge(SOC). Compared with the results of single-point measurement, the spatial displacement distribution obtained from three-dimensional(3D) scanning suggests the full-field thickness evolution of the entire cell scale, which is more feasible and efficient to provide full-field information for supporting pouch cell design and pack integration.