High-performance solid-state lithium metal batteries achieved by interface modification

Garnet-structured ceramic electrolyte Li_(6.75)La_(3)Zr_(1.75)Ta_(0.25)O_(12)(LLZTO)attracts significant consideration in solid-state Li metal batteries due to its wide electrochemical window and favorable compatibility with Li metal.However,the deployment of LLZTO is severely hampered by poor contact between LLZTO and Li metal anode.In this paper,an ultra-thin Al-Si interface buffer layer(10 nm)is constructed on LLZTO by a magnetron sputtering method,which allows superior wetting of Li onto the LLZTO surface due to the alloying reaction between the Al-Si layer and Li metal.The resulting Li/Al-Si coated LLZTO(ASL)/Li symmetrical cell delivers an interfacial resistance of 15.0Ωcm^(-2),which is much lower than that of 1140.3Ωcm^(-2)for the bare LLZTO symmetrical cell.Moreover,the Li/ASL/Li symmetrical cells exhibit stable plating/striping performance(800 h)with small voltage hysteresis at 1.0 mA cm^(-2).Besides,the full cell with LiFePO_(4)cathode reveals a high capacity of 124.1 mA h g^(-1)after 600 cycles at 0.5C with a lowcapacity decay of 0.032%per cycle.We believe this work will facilitate the development of solid-state rechargeable batteries.

Electrochemically induced phase transition in a nanoflower vanadium tetrasulfide cathode for high-performance zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) are promising contenders for large-scale energy storage with the merits of their low cost,high safety,environmental friendliness,and competitive gravimetric energy density.Nevertheless,suitable cathode materials with long cycle life and adequate capacity are still rare.Herein,we report a nanoflower vanadium tetrasulfide/carbon nanotubes (VS_(4)/CNTs) cathode with high Znstorage performance.We propose a phase transition reaction mechanism from VS_(4)to zinc pyrovanadate in the initial cycles and a reversible intercalation mechanism for Zn^(2+) in zinc pyrovanadate during subsequent cycles.As a result,the cathode delivers a high discharge capacity of 265 mAh g^(-1)at 0.25 A g^(-1)and 182 m Ah g^(-1)at 7 A g^(-1).In addition,the cathode exhibits a long-term cyclability with 93%capacity retention over 1200 cycles at 5 A g^(-1).VS_(4)/CNTs with superior electrochemical performance is a hopeful cathode material in AZIBs.

Advanced cellulose-based materials toward stabilizing zinc anodes

Rechargeable aqueous zinc metal batteries(RAZMBs) have received extensive attention for large-scale energy storage systems due to the merits of Zn anodes, including moderate volumetric and gravimetric energy density, low redox potential, abundant reserve, low cost and impressive intrinsic safety. However, Zn anodes suffer from a series of adverse reactions(dendrite growth,hydrogen evolution, and surface passivation) resulting in low Coulombic efficiency, large polarization, and unsatisfied cycling performance, which inevitably hinder the wide application of RAZMBs. To address the above issues, cellulose-based materials are widely used for Zn anode protection because of their unique physical and chemical properties and other advantages such as biocompatibility, non-toxicity, degradability and easy extraction. In order to better understand the current progress in cellulosebased materials for the Zn anode protection, we have classified and summarized the relevant literatures. In this review, we summarize and elaborate the causes of poor reversibility for Zn anodes, including dendrite formation, hydrogen evolution, and surface passivation. Subsequently, the effective strategies(anode interfacial engineering, gel electrolyte optimization, and separator modification) of cellulose-based materials toward stabilizing Zn anodes are overviewed. In the end, the existing challenges and prospects of cellulose-based materials in Zn anode protection are summarized to shed light on future work.

POLAR伽马暴瞬时辐射偏振测量与脉冲星导航试验研究进展

伽马射线暴(简称伽马暴,gamma-ray burst,GRB)从发现至今已超过半个世纪,其观测样本得到了极大提高,理论研究也取得了瞩目的成果.但对伽马暴的研究还有诸多未解之谜,例如伽马暴的分类和起源、爆发过程中的喷流成分、辐射机制和磁场构型等.其中,对于伽马暴的辐射机制,科学家提出了多种理论模型,不同的模型对于伽马暴爆发期间产生的伽马射线偏振状态的预测不同.因此,采用测量偏振的方法,可以对伽马暴的爆发机制进行研究,并且理解产生伽马射线的极端相对论喷流的结构及其磁场的构型等物理问题.然而,测量伽马暴瞬时辐射过程中的偏振具有极高的挑战性.伽马暴偏振探测仪(POLAR)是一台专门用于高精度测量伽马暴瞬时辐射偏振的空间望远镜,2016年9月15日搭载于我国的空间实验室“天宫二号”成功发射.POLAR在轨共探测到55个确认的伽马暴,首批给出了5个伽马暴的高精度偏振测量结果,最终统计性地给出了14个伽马暴的偏振测量结果.同时,POLAR还观测到了Crab脉冲星信号和太阳X射线耀发事件等.本文简要介绍POLAR,并给出其在轨伽马暴偏振测量结果以及利用观测到的脉冲星信号所开展的导航试验研究进展情况.此外,简要介绍POLAR的后续实验项目POLAR-2,对其未来的科学探测能力进行展望.

In-situ topotactic construction of novel rod-like Bi_(2)S_(3)/Bi_(5)O_(7)I p-n heterojunctions with highly enhanced photocatalytic activities

In this work,a novel Bi_(2)S_(3)/Bi_(5)O_(7)I p-n heterojunction with three-dimensional rod-like nanostructure was successfully constructed through an in-situ topotactic ion exchange approach.A possible evolution mech-anism from Bi_(5)O_(7)I nanobelts(NBs)into Bi_(2)S_(3)/Bi_(5)O_(7)I rod-like heterostructures(BSI RHs)was proposed,depicting the self-assembly process of internal Bi_(5)O_(7)I NBs and outside networks interwoven by Bi_(2)S_(3)nanorods(NRs),which abided by the Ostwald ripening and epitaxial growth.Owing to the formation of p-n heterojunction and rich oxygen vacancies(OVs),the visible-light absorption ability and separation of photogenerated charge carriers of BSI RHs were highly promoted,leading to a greatly improved photocatalytic ability than that of Bi_(2)S_(3)and Bi_(5)O_(7)I.BSI-1 exhibited the strongest photocatalytic performance,and almost all rhodamine B(RhB)and Pseudomonas aeruginosa(P.aeruginosa)can be thoroughly removed within 90 min.Moreover,a possible photocatalytic mechanism of BSI RHs was proposed based on the tests of active species trapping,electron spin resonance(ESR),photoelectrochemistry(PEC),and photoluminescence(PL)combined with the density functional theory(DFT)simulated computation,vali-dating the dominating roles of·O_(2)^(−)and h+during the photocatalytic process.This work is expected to motivate further efforts for developing novel heterostructures with highly efficient photocatalytic performances,which presents a promising application prospect in the fields of energy and environment.

Rechargeable Na-CO_(2) Batteries Starting from Cathode of Na2CO_(3) and Carbon Nanotubes

Na-CO_(2) batteries have attracted signifcant attentions due to their high energy density and efective utilization of greenhouse gas CO_(2).However,all reported Na-CO_(2) batteries employ excessive preloaded metal Na,which will lead to safety issues such as dendrite formation and short circuit.In addition,the charging mechanism of reported Na-CO_(2) batteries is not very clear.Here we report the Na-CO_(2) batteries,starting from the cathode of cheap Na2CO_(3) and multiwalled carbon nanotubes(CNTs).Due to the efective electron transfer and high reactivity,the decomposition of Na2CO_(3) and CNTs could take place under 3.8 V.Te charging mechanism of 2Na2CO_(3)+C�→4Na+3CO_(2) without any side reactions is revealed by in/ex situ techniques such as Raman,gas chromatograph,and optical microscope.Dendrite-free Na can quantitatively deposit on the Super P/Al anode because of large specifc surface area and low nucleation barrier of the anode for Na plating.Te batteries could deliver an energy density of 183 Wh kg−1(based on the whole mass of the pouch-type batteries,4 g)with stable cycling performance.Tis work reveals that safe rechargeable Na-CO_(2) batteries could be constructed by cheap Na2CO_(3) and multiwalled carbon nanotubes.

Boosting the zinc storage performance of vanadium dioxide by integrated morphology engineering and carbon nanotube conductive networks

Vanadium dioxide(VO_(2)) with the advantages of high theoretical capacity and tunnel structure has attracted considerable promising candidates for aqueous zinc-ion batteries.Nevertheless,the intrinsic low electronic conductivity of VO_(2) results in an unsatisfactory electrochemical performance.Herein,a flower-like VO_(2)/carbon nanotubes(CNTs)composite was obtained by a facile hydrothermal method.The unique flower-like morphology shortens the ion transport length and facilitates electrolyte infiltration.Meanwhile,the CNT conductive networks is in favor of fast electron transfer.A highly reversible zinc storage mechanism was revealed by ex-situ X-ray diffraction and X-ray photoelectron spectroscopy.As a result,the VO_(2)/CNTs cathode exhibits a high reversible capacity(410 mAh·g^(−1)),superior rate performance(305 mAh·g^(−1)at 5 A·g^(−1)),and excellent cycling stability(a reversible capacity of 221 mAh·g^(−1)was maintained even after 2000 cycles).This work provides a guide for the design of high-performance cathode materials for aqueous zinc metal batteries.