Repurposing EV Batteries for Storing Solar Energy

1.Introduction Carbon neutrality has emerged as a global goal due to its pivotal role in addressing the challenges of global climate change.Before the United Nations Climate Summit was held in November 2020,124 countries promised to reach net-zero emissions[1].Solar energy is one of the important renewable energy sources that significantly curtail carbon emissions originating from fossil fuels.

Revisiting the gravity laws of inter-city mobility in megacity regions

Inter-city mobility is one of the most important issues in the UN Sustainable Development Goals,as it is essential to access the regional labour market,goods and services,and to constrain the spread of infectious diseases.Although the gravity model has been proved to be an effective model to describe mobility among settlements,knowledge is still insufficient in regions where dozens of megacities interact closely and over 100 million people reside.In addition,the existing knowledge is limited to overall population mobility,while the difference in inter-city travel with different purposes is unexplored on such a large geographic scale.We revisited the gravity laws of inter-city mobility using the 2.12 billion trip chains recorded by 40.48 million mobile phone users’trajectories in the Jing-Jin-Ji Region,which contains China’s capital Beijing.Firstly,unlike previous studies,we found that non-commuting rather than commuting is the dominant type of inter-city mobility(89.3%).Noncommuting travellers have a travel distance 42.3%longer than commuting travellers.Secondly,we developed more accurate gravity models for the spatial distribution of inter-city commuting and non-commuting travel.We also found that inter-city mobility has a hierarchical structure,as the distribution of inter-city travel volume follows Zipf’s law.In particular,the hierarchy of non-commuting travel volume among the cities is more in line with an ideal Zipf distribution than commuting travel.Our findings contribute to new knowledge on basic inter-city mobility laws,and they have significant applications for regional policies on human mobility.

通过4-磺基苯甲酸单钾盐抑制离子迁移以实现效率为22.7%的稳定钙钛矿太阳能电池

晶界处的深能级缺陷和严重的卤素离子迁移对进一步提高钙钛矿太阳能电池的稳定性和效率以及消除迟滞现象提出了严峻的挑战.本文报道了一种大尺寸强配位的有机阴离子晶界锚定策略来抑制离子迁移并钝化薄膜缺陷.本策略通过将含有大尺寸有机阴离子的钾盐(4-磺基苯甲酸单钾盐,SAMS)加入到钙钛矿前驱液中来实现.研究表明,阴离子两端的C=O和/或S=O能够与未配位的Pb^(2+)离子和/或卤化物空位之间发生强配位作用,阴离子中的–OH能够与甲脒阳离子形成氢键,以上化学作用使阴离子紧紧锚定在晶界处.SAMS不仅能够钝化浅能级缺陷,而且能够更有效地钝化深能级缺陷.该晶界锚定策略能降低钙钛矿薄膜的缺陷密度、延长载流子寿命和抑制离子迁移,提高电池的效率和稳定性以及消除迟滞效应.结果表明,基于SAMS改性的电池实现了22.7%的效率,而对照器件显示了20.3%的效率.未封装改性的器件在60℃加热老化1320小时后几乎没有发生衰减.

Growth Mechanism,Modified Morphology and Optical Properties of Coral-like BaTiO_3 Architecture through CTAB Assisted Synthesis

Three-dimensional hierarchical structure coral-like BaTiO3 nanoparticles have been self-assembled by a facile one step hydrothermal method. Cetyltrimethyl ammonium bromide(CTAB),Ba(OH)2·8H2O and tetrabutyl titanate have been used as precursors. The prepared Ba TiO3 exhibits cubic perovskite phase at room temperature,and the coral-like architecture is a micro-nano hiberarchy consisted of dendrimer-like structure and trunk-like structure. By adjusting the hydrothermal duration and the precursor substances,a surfactant induced mechanism is proposed to understand the self-assembly process. UV-vis measurement demonstrates that the as-prepared Ba TiO3 nanoparticles exhibit dozens of times overwhelming absorptive character compared to the ordinary nanospheres at ultraviolet band,which is benefited from the coral-like porous framework. Moreover,halogen anions( F,Cl,Br,and I) have been chosen to adjust the coral-like Ba TiO3 physical properties. Results show the halogen doping produces distinct modulation effect on the grain size,UV-vis absorbance and photoluminescence properties of the materials. The coral-like BaTiO3 nanoparticle and its halogen modified ramifications offer significant opportunities to develop nano-laser devices,photon detectors,photocatalyst based on BaTiO3 perovskite materials.

Synthesis and optical properties of novel Gd^(3+)-doped BaZn_(2)(PO_(4))_(2)glass-ceramics for radiation detection applications

45 P_(2)O_(5)-15 BaO-25 ZnO-15 B2O_(3)glasses doped with different concentrations(0 mol%,0.1 mol%,0.25 mol%,0.5 mol%,and 0.75 mol%)of Gd^(3+)were prepared by a melt-quenching method and treated to fabricate glass-ceramics containing BaZn_(2)(PO_(4))_(2)crystals by controllable crystallization.The structural,optical,and dosimetric properties were investigated.FTIR spectra indicate that the glasses are composed of[PO_(4)],[BO_(3)],and[BO_(4)]basic structural units.The XRD pattern analysis indicates that the samples contain BaZn_(2)(PO_(4))_(2)crystals.In the photoluminesce nce(PL)spectra,two emission bands are observed at 307 and 313 nm due to the^(6)P_(5/2)→^(8)S_(7/2)and^(6)P_(7/2)→^(8)S_(7/2)transitions of Gd^(3+),respectively.The OSL dosimetric properties of glass-ceramics were studied further under beta radiation of90Sr.The optimal Gd^(3+)doping concentration of 0.5 mol%was determined.The fading of the OSL signal shows that the CW-OSL signal of Gd^(3+)-doped BaZn_(2)(PO_(4))_(2)glass-ceramics decays by about 58.95%within120 h,and the intensity remains stable thereafter.The thermoluminescence(TL)curve has three peaks at 164,240,and 344℃.Minimum detectable dose(MDD)of the 0.5 mol%Gd^(3+)-doped BaZn_(2)(PO_(4))_(2)glass-ceramics was calculated as 0.675 mGy.The samples also exhibit good signal reusability and a broad linear dose-response range(0.3-500 Gy).Results show the excellent dosimetric properties of Gd^(3+)-doped BaZn_(2)(PO_(4))_(2)glass-ceramics and their potential application in radiation dosimetry.