Quasi-Solid-State Ion-Conducting Arrays Composite Electrolytes with Fast Ion Transport Vertical-Aligned Interfaces for All-Weather Practical Lithium-Metal Batteries

The rapid improvement in the gel polymer electrolytes(GPEs)with high ionic conductivity brought it closer to practical applications in solid-state Li-metal batteries.The combination of solvent and polymer enables quasi-liquid fast ion transport in the GPEs.However,different ion transport capacity between solvent and polymer will cause local nonuniform Li+distribution,leading to severe dendrite growth.In addition,the poor thermal stability of the solvent also limits the operating-temperature window of the electrolytes.Optimizing the ion transport environment and enhancing the thermal stability are two major challenges that hinder the application of GPEs.Here,a strategy by introducing ion-conducting arrays(ICA)is created by vertical-aligned montmorillonite into GPE.Rapid ion transport on the ICA was demonstrated by 6Li solid-state nuclear magnetic resonance and synchrotron X-ray diffraction,combined with computer simulations to visualize the transport process.Compared with conventional randomly dispersed fillers,ICA provides continuous interfaces to regulate the ion transport environment and enhances the tolerance of GPEs to extreme temperatures.Therefore,GPE/ICA exhibits high room-temperature ionic conductivity(1.08 mS cm^(−1))and long-term stable Li deposition/stripping cycles(>1000 h).As a final proof,Li||GPE/ICA||LiFePO_(4) cells exhibit excellent cycle performance at wide temperature range(from 0 to 60°C),which shows a promising path toward all-weather practical solid-state batteries.

Bacterial Cellulose Composite Solid Polymer Electrolyte With High Tensile Strength and Lithium Dendrite Inhibition for Long Life Battery

The development of metallic lithium anode is restrained by lithium dendrite growth during cycling.The solid polymer electrolyte with high mechanical strength and lithium ion conductivity could be applied to inhibit lithium dendrite growth.To prepare the high-performance solid polymer electrolyte,the environment-friendly and cheap bacterial cellulose(BC)is used as filler incorporating with PEO-based electrolyte owing to good mechanical properties and Li salts compatibility.PEO/Li TFSI/BC composite solid polymer electrolytes(CSPE)are prepared easily by aqueous mixing in water.The lithium ion transference number of PEO/Li TFSI/BC CSPE is 0.57,which is higher than PEO/Li TFSI solid polymer electrolyte(SPE)(0.409).The PEO/Li TFSI/BC CSPE exhibits larger tensile strength(4.43 MPa)than PEO/Li TFSI SPE(1.34 MPa).The electrochemical window of composite electrolyte is widened 1.43 V by adding BC.Density functional theory calculations indicate that flex of PEO chains around Li atoms is suppressed,suggesting the enhanced lithium ion conductivity.Frontier molecular orbitals results suggest that an unfavorable intermolecular charge transfer lead to achieve higher potential for BC composite electrolyte.All solid-state Li metal battery with PEO/Li TFSI/BC CSPE delivers longer cycle life for 600 cycles than PEO/Li TFSI SPE battery(50 cycles).Li symmetrical battery using PEO/Li TFSI/BC CSPE could be stable for 1160 h.

高负载棉花纤维素基气凝胶自支撑电极用于锂硫电池

锂硫电池因具有2600 Wh kg–1的高能量密度,而备受人们关注.但由于硫的负荷和利用率低,阻碍了硫的商品化.在此,本文设计了纤维素基石墨烯-碳复合气凝胶(CCA)自支撑电极来提高锂硫电池的性能. CCA具有低密度(0.018 g cm–3)、大比表面积(657.85 m2g–1)、高孔隙率(96%)、显著的电解质吸附(42.25倍)等独特的物理结构,有助于提高硫的质量负荷和利用率.与Al(约49%)相比, CCA表现出优良的硫利用效率(86%),在9.11 mgS负荷下可达到8.60 mAh cm–2的大面积容量,有助于实现锂硫电池的商业化进程.同时,由于其灵活性和对电响应信号的高灵敏度, CCA表现出优异的脉冲传感应用潜力.

离子液体体系中电化学沉积纳米锌修饰碳布作为抑制锂枝晶的主体框架

高比容量、高能量密度锂金属负极的应用受到了电池循环过程中锂枝晶不规则生长的限制.本文通过在表面修饰纳米锌的3D碳布框架中熔融浸润锂金属制备成复合锂金属负极.利用电化学沉积在物理化学性质稳定的离子液体中对碳布修饰锌纳米层.在高温下,将熔融锂浸入碳布-纳米锌的框架制备出复合的锂金属负极.稳定的框架主体降低了有效电流密度和界面电阻,诱导锂的均匀生长,抑制了锂枝晶的形成和生长,因此缓解了锂负极的体积膨胀和粉化情况.基于以上原因,3D碳布-锌-锂金属复合负极组成的对称电池表现出了较低的过电势和长循环稳定性.在锂金属/磷酸铁锂全电池中展示出了超长的电化学循环稳定性.

Phase boundary engineering of metal-organic-framework-derived carbonaceous nickel selenides for sodium-ion batteries

Nano Research volume 13,pages2289–2298(2020)Cite this article 347 Accesses 1 Altmetric Metrics details Abstract Sodium-ion batteries(SIBs)are promising power sources due to the low cost and abundance of battery-grade sodium resources,while practical SIBs suffer from intrinsically sluggish diffusion kinetics and severe volume changes of electrode materials.Metal-organic framework(MOFs)derived carbonaceous metal compound offer promising applications in electrode materials due to their tailorable composition,nanostructure,chemical and physical properties.Here,we fabricated hierarchical MOF-derived carbonaceous nickel selenides with bi-phase composition for enhanced sodium storage capability.As MOF formation time increases,the pyrolyzed and selenized products gradually transform from a single-phase Ni3Se4 into bi-phase NiSex then single-phase NiSe2,with concomitant morphological evolution from solid spheres into hierarchical urchin-like yolk-shell structures.As SIBs anodes,bi-phase NiSex@C/CNT-10h(10 h of hydrothermal synthesis time)exhibits a high specific capacity of 387.1 mAh/g at 0.1 A/g,long cycling stability of 306.3 mAh/g at a moderately high current density of 1 A/g after 2,000 cycles.Computational simulation further proves the lattice mismatch at the phase boundary facilitates more interstitial space for sodium storage.Our understanding of the phase boundary engineering of transformed MOFs and their morphological evolution is conducive to fabricate novel composites/hybrids for applications in batteries,catalysis,sensors,and environmental remediation.

Highly Stretchable and Transparent Ionic Conductor with Novel Hydrophobicity and Extreme-Temperature Tolerance

Highly stretchable and transparent ionic conducting materials have enabled new concepts of electronic devices denoted as iontronics,with a distinguishable working mechanism and performances from the conventional electronics.However,the existing ionic conducting materials can hardly bear the humidity and temperature change of our daily life,which has greatly hindered the development and real-world application of iontronics.Herein,we design an ion gel possessing unique traits of hydrophobicity,humidity insensitivity,wide working temperature range(exceeding 100℃,and the range covered our daily life temperature),high conductivity(10^(-3)~10^(-5) S/cm),extensive stretchability,and high transparency,which is among the bestperforming ionic conductors ever developed for flexible iontronics.Several ion gel-based iontronics have been demonstrated,including large-deformation sensors,electroluminescent devices,and ionic cables,which can serve for a long time under harsh conditions.The designed material opens new potential for the real-world application progress of iontronics.