The Role of Grain Boundaries in Organic-Inorganic Hybrid Perovskite Solar Cells and its Current Enhancement Strategies:A Review

Grain boundaries(GBs)in perovskite polycrystalline films are the most sensitive place for the formation of the defect states and the accumulation of impurities.Thus,abundant works have been carried out to explore their properties and then try to solve the induced problems.Currently,two important issues remain.First,the role of GBs in charge carrier dynamics is unclear due to their component complexity/defect tolerance nature and the insufficiency in testing accuracy.Some works conclude that GBs are benign,while others consider GBs as carrier recombination centers.Things for sure are the deterioration in ion transport and perovskite decomposition.Second,to solve the known hazards of GBs,a lot of additives have been added to anchoring ions and passivate defects.But in most of those works,GBs and perovskite surfaces are treated in the same manner ignoring the fact that GB is essentially a homogeneous junction in a narrow and slender space,while surface is a heterogeneous junction with a stratified structure.In this review,we focus on works insight into GBs and additives for them.Additionally,we also discuss the prospects of the maturity of GB exploration toward upscaling the manufacture of perovskite photovoltaic and related optoelectronic devices.

Boosting Lean Electrolyte Lithium-Sulfur Battery Performance with Transition Metals: A Comprehensive Review

Lithium–sulfur(Li–S) batteries have received widespread attention, and lean electrolyte Li–S batteries have attracted additional interest because of their higher energy densities. This review systematically analyzes the effect of the electrolyte-to-sulfur(E/S) ratios on battery energy density and the challenges for sulfur reduction reactions(SRR) under lean electrolyte conditions. Accordingly, we review the use of various polar transition metal sulfur hosts as corresponding solutions to facilitate SRR kinetics at low E/S ratios(< 10 μL mg~(-1)), and the strengths and limitations of different transition metal compounds are presented and discussed from a fundamental perspective. Subsequently, three promising strategies for sulfur hosts that act as anchors and catalysts are proposed to boost lean electrolyte Li–S battery performance. Finally, an outlook is provided to guide future research on high energy density Li–S batteries.

Robust In-Zr Metal-Organic Framework Nanosheets as Ultrathin Interlayer Toward High-Rate and Long-Cycle Lithium-Sulfur Batteries

Lithium-sulfur(Li-S)batteries have great potential as the next generation of high-energy-density storage systems.However,the practical viability of Li-S batteries is largely hampered by undesirable shuttling behavior and sluggish conversion kinetics of polysulfides.Herein,a multifunctional separatormodified layer(In/Zr-BTB nanosheets)with the merits of robust structures and efficient catalytic metal sites has been presented.In/Zr-BTB nanosheets inherit the stable structure from Zr-BTB and strengthen the catalytic performance due to the introduction of highly catalytic species indium via metal-ion exchange.The thickness and areal mass loading of the modified layer are only 260 nm and 0.011 mg/cm2,respectively.Nevertheless,the ultrathin modification layers with efficient catalytic species,compact structures,and uniform pore channels can realize fast Li+transport,effective polysulfide interception,and rapid catalytic conversion.Therefore,the In/Zr-BTB@PP cell with a high sulfur content of 80 wt%could maintain high capacity retention of 85.6%with a low capacity fading rate of 0.048%per cycle after 300 cycles even at a high current rate of 2 C.This work opens a new door toward the design of versatile metal-organic framework(MOF)nanosheets and multifunctional separators for high-energy-density Li-S batteries.

中国麋鹿种群重建35年:历程、成就与挑战

迁地保护是《生物多样性公约》的重要内容,是"爱知生物多样性目标"的目标之一,也是《中国生物多样性保护战略与行动计划》(2011-2030)的战略任务和优先行动。麋鹿(Elaphurus davidianus)是国家I级重点保护野生动物。中国麋鹿经历了本土野外灭绝、圈养种群引至国外、国外圈养种群重引入国内、种群复壮、迁地保护、放归野外,最终建立野生种群的历程。北京麋鹿苑自1985年重引入38只后,于1991年就已恢复到60-80只的麋鹿基础种群。种群扩大后,逐年向外输出,35年来共计输出546只,苑内数量维持在150只左右。江苏大丰1986年引入麋鹿39只,于1990年达到78只的基础种群,2019年底种群数量发展至5,016只,是建群时的129倍。大丰自1995年开始向外输出麋鹿,至2020年底共计输出164只。麋鹿分布点从重引入时的2个发展至2020年的81个,已几乎全面覆盖麋鹿灭绝前原有的栖息地。其中野生种群分布在6处,数量总计达2,855只。中国麋鹿野生种群的重建是野生动物迁地保护和回归自然的典范,为全球野外灭绝野生动物种的保护贡献了中国智慧。然而,当前麋鹿保护也遇到诸多挑战:(1)尚没有国家层级的麋鹿保护整体规划,缺乏统一的监测平台与规范;(2)麋鹿遗传多样性匮乏,种群抗风险能力差;(3)野生种群分布不广,且数量较小,不利于野生种群的稳定性;(4)麋鹿种群与环境承载力的矛盾凸显,不利于麋鹿种群的健康发展;(5)麋鹿保护缺乏国际交流机制,不利于麋鹿相关研究的国际交流。因此,麋鹿的保护和研究仍任重道远,今后需加强各地麋鹿种群生态监测,建立麋鹿共享数据库;采用技术手段增加遗传多样性,建立麋鹿种质资源库;建立更多野生种群,以增加麋鹿野生种群的稳定性,使这一野外灭绝物种能够真正实现自然回归。

主要利益相关方在履行《名古屋议定书》中的关系与义务

生物遗传资源及其相关传统知识的获取与惠益分享(Access and Benefit Sharing,ABS)涉及三个主要利益相关方,即提供方、使用方和监管方。在我国履行《名古屋议定书》的过程中,需深刻理解《名古屋议定书》中对于提供方、使用方和监管方的相关规定,分析三方关系内涵及各自义务,对有效履行《名古屋议定书》具有重要意义。本文提出,为促进公平和公正的惠益分享,提供方有义务明确生物遗传资源的原产地并保护和可持续利用原产的生物遗传资源,确定生物遗传资源的原始持有社区和相关传统知识的原始持有人(或地方社区);通过调查、登记和编目,分析遗传资源的起源、形成及利用历史,建立当地生物遗传资源及相关传统知识的档案;通过ABS知识培训,提高参与"获取与惠益分享"事务的能力,特别是与使用方谈判ABS协议的能力。使用方有义务履行国际公约规定的"事先知情同意"和"共同商定条件"原则,在征得土著和地方社区的事先知情同意和实质性参与下,与土著和地方社区经共同商定条件,签订体现公平惠益分享的ABS协议;使用方要尊重土著和地方社区对保护和提供生物遗传资源的贡献,制定行为守则,履行社会责任;还要在论文发表及专利申请时披露所使用遗传资源及相关传统知识的来源和原产地。监管方有责任建立完善的ABS政策和法规体系;建立ABS信息交换机制,发布ABS相关信息;规定提交获取申请所要求的材料,提供"ABS协议"的模本,并审查和批准"ABS协议",签发"合法来源证书";并通过建立检查点,监督和监测ABS协议的履行。

Cobalt-embedded 3D conductive honeycomb architecture to enable high-sulphur-loading Li-S batteries under lean electrolyte conditions

High sulphur loading and lean electrolyte conditions are important to achieve the high theoretical energy density of lithiumsulphur(Li-S)batteries.However,serious problems such as low sulphur utilization and fast capacity fade are typically experienced under low electrolyte/sulphur(E/S)ratios and high sulphur loading conditions.To address these issues,a cobaltcontaining three-dimensional conductive honeycomb(Co@N-HPC)is proposed in this work as a material for sulphur cathodes.The good electrical conductivity and high density of catalytic sites of(Co@N-HPC)allow fast redox kinetics of lithium polysulfide(LiPS)in high-sulphur-loading electrodes.In addition,the hierarchical structure and good wettability by the electrolyte of Co@NHPC facilitates electrolyte penetration and LiPS conversion,leading to a high utilization of sulphur under lean electrolyte conditions.Therefore,at a current density of 0.2 C,a volumetric capacity of 1,410 mAh·cm^(−3)was attained with a sulphur loading of 5.1 mg·cm^(−2)and an E/S ratio of 5μL·mg^(−1).This work provides ideas for the development of lean electrolyte Li-S batteries with a high sulphur loading.

Structural Isomerization in Cu(I)Clusters:Tracing the Cu Thermal Migration Paths and Unveiling the Structure-Dependent Photoluminescence

Revealing structural isomerization in metal clusters would bridge a huge structural gap between small molecular isomerization and solid–solid phase transformation.However,genuine structural isomerism in metal clusters is still rare.In this work,we report the first example of structural isomerismin Cu clusters.By utilizing the coordination flexibility of alkyne to enable the migration of partial Cu atoms in Cu metal cores,two Cu_(15)cluster complexes(Cu_(15)-a and Cu_(15)-c)possessing identical composition but different metal core structures have been successfully isolated.Interestingly,although the structure of Cu_(15)-a can be retained in CH_(2)C_(l2)solution below 27°C,it will gradually change to give an intermediate state,Cu_(15)-b,as the temperature rises(at about 31°C)before it eventually transforms into Cu_(15)-c(at 40∼65°C).Significantly,atomically precise Cu_(15)-b clearly provides footprints for tracing the thermal migration process of Cu atoms during the thermal transformation from Cu_(15)-a to Cu_(15)-c.In addition,Cu_(15)-a and Cu_(15)-c exhibit diverse crystallization-induced emission enhancement phenomena.Crystalline Cu_(15)-c displays redshifted photoluminescence(820 nm)compared with Cu_(15)-a(726 nm)due to the shorter mean Cu···Cu distance in Cu_(15)-c.Notwithstanding,crystalline Cu_(15)-a exhibits much more intense photoluminescence at room temperature than that in Cu_(15)-c,which might be attributed to the stronger intermolecular C–H⋯πinteractions in Cu_(15)-a.These results indicate that cluster isomerism provides valuable opportunities for insight into the structure–property relationships and understanding the complex evolution of phase transformation in nanometallic solids.