Lithium-Metal-Free Sulfur Batteries with Biochar and Steam-Activated Biochar-Based Anodes from Spent Common Ivy

Lithium-sulfur batteries are emerging as sustainable replacements for current lithium-ion batteries.The commercial viability of this novel type of battery is still under debate due to the extensive use of highly reactive lithium-metal anodes and the complex electrochemistry of the sulfur cathode.In this research,a novel sulfur-based battery has been proposed that eliminates the need for metallic lithium anodes and other critical raw materials like cobalt and graphite,replacing them with biomass-derived materials.This approach presents numerous benefits,encompassing ample availability,cost-effectiveness,safety,and environmental friendliness.In particular,two types of biochar-based anode electrodes(non-activated and activated biochar)derived from spent common ivy have been investigated as alternatives to metallic lithium.We compared their structural and electrochemical properties,both of which exhibited good compatibility with the typical electrolytes used in sulfur batteries.Surprisingly,while steam activation results in an increased specific surface area,the non-activated ivy biochar demonstrates better performance than the activated biochar,achieving a stable capacity of 400 mA h g^(−1)at 0.1 A g^(−1)and a long lifespan(>400 cycles at 0.5 A g^(−1)).Our results demonstrate that the presence of heteroatoms,such as oxygen and nitrogen positively affects the capacity and cycling performance of the electrodes.This led to increased d-spacing in the graphitic layer,a strong interaction with the solid electrolyte interphase layer,and improved ion transportation.Finally,the non-activated biochar was successfully coupled with a sulfur cathode to fabricate lithium-metal-free sulfur batteries,delivering a specific energy density of~600 Wh kg^(−1).

黄铜集流体在无负极锂金属电池中的应用研究

虽然无负极锂金属电池(AF-LMBs)具有能量密度高、结构简单等优势,但是金属锂在负极集流体界面不可逆的沉积/剥离过程以及与电解液之间的副反应会大量消耗电池中有限的活性锂,导致电池容量迅速衰减。开发高性能的负极集流体是提升AF-LMBs循环寿命的有效策略之一。因此,本文研究了商业黄铜箔(F-Cu-Zn)作为负极集流体在AF-LMBs中的电化学性能,并且结合多种表征技术揭示了F-Cu-Zn电极在循环过程中的结构演变。结果表明:与商业铜箔(F-Cu)相比,F-Cu-Zn含有丰富的亲锂位点,诱导金属锂均匀成核与生长,所组装的Cu-Zn||NCM712软包全电池的室温循环寿命从75次增加至117次。此外,F-Cu-Zn电极中的Zn元素会在循环过程中不断溶解,最终在电极表层形成三维多孔结构。

无负极锂金属电池的挑战与发展

无负极锂金属电池因极高的理论容量、能量密度和低成本的优势成为学术热点。但由于铜箔的疏锂性和金属锂的高活性,导致了锂沉积/剥离不均匀,从而产生锂枝晶和锂消耗过快等诸多问题,限制了实际应用。对无负极锂金属电池的优势、挑战以及解决方案进行了全面梳理,从修饰集流体、构筑稳定固态电解质界面(SEI)膜、引入补锂技术以及优化电解液四个改进策略进行了详细论述,并讨论了负极侧影响金属锂沉积/剥离的机制、正极额外锂源的优势以及电解液对无负极锂金属电池可逆性的影响,总结了四种策略的优缺点和未来的发展方向。

Investigation of polysulfone film on high-performance anode with stabilized electrolyte/electrode interface for lithium batteries

Lithium metal has been considered to be the most promising anode material for the new generation of energy-storage system.However,challenges still stand in protecting lithium metal from spontaneous reactions with electrolytes and preventing the dendritic propagation,both of which would lead to undesirable decrease in Coulombic efficiency.Polysulfone(PSf)membrane with high rigidity and free-volume cavities of approximately 0.3 nm was employed to provide a stable interface on the surface of anodic electrode.The isotropic channels were constructed by the interconnected and uniformly distributed free volumes in the polymer matrix,and were expected to be swelled by solvent molecules and anions of lithium salt and to allow Li+ions to pass through onto the electrode surface.As a result,dendrite-free morphology of deposited lithium was observed.The stabilized interface arose from the PSf film was verified by the promoted performances of Cu|Li cells and steady voltage polarization of Li|Li cells.The full cell with PSf coated anode exhibited excellent cyclability(85%capacity retention rate over 400 cycles at 1C)and an outstanding rate capability(117 m Ah g-1 at 5C).The beneficial performances were further verified by the EIS results.This work provides a new strategic idea to settle the dendritic problems of Li metal anodes.

Free-standing ternary metallic sulphides/Ni/C-nanofiber anodes for high-performance lithium-ion capacitors

As a promising energy-storage device,the hybrid lithium-ion capacitor coupling with both a large energy density battery-type anode and a high power density capacitor-type cathode is attracting great attention.For the sake of improving the energy density of hybrid lithium-ion capacitor,the free-standing anodes with good electrochemical performance are essential.Herein,we design an effective electrospinning strategy to prepare free-standing MnS/Co4S3/Ni3S2/Ni/C-nanofibers(TMSs/Ni/C-NFs)film and firstly use it as a binder-free anode for hybrid lithium-ion capacitor.We find that the carbon nanofibers can availably prevent MnS/Co4S3/Ni3S2/Ni nanoparticles from aggregation as well as significantly improve the electrochemical performance.Therefore,the binder-free TMSs/Ni/C-NFs membrane displays an ultrahigh reversible capacity of 1246.9 m Ah g-1at 100 m A g-1,excellent rate capability(398 mAh g-1 at2000 mA g-1),and long-term cyclic endurance.Besides,we further assemble the hybrid lithium-ion capacitor,which exhibits a high energy density of 182.0 Wh kg-1at 121.1 W kg-1(19.0 Wh kg-1 at 3512.5 W kg-1)and remarkable cycle life.

三维锂金属负极的研究进展

金属锂具有高的理论比容量(3860 mAh·g^-1),低的电极电位(-3.04 V与标准氢电极相比)和低的密度(0.53 g·cm^-3),是最有前途的锂二次电池用的负极材料。但仍存在循环过程中枝晶生长及其导致的低库伦效率、短循环寿命等问题。而3D锂金属负极因具有高比表面积和内部空腔能有效缓解上述问题。特别是纳米技术的发展为3D锂金属负极提供了更高效的形貌与结构。基于金属基和碳基3D锂金属负极对三维锂金属负极的设计及研究进展进行了详细的概述。

低成本无钴高镍正极的挑战与策略

高镍正极材料是一类综合性能优越的锂离子电池正极材料,它不仅可以达到比传统钴酸锂更高的能量密度,而且成本更低、更加环保,在动力电池市场具有巨大优势。为了进一步降低储能器件成本来适应与日俱增的能源需求,开发无钴高镍正极材料成为新的研究焦点。本文从镍酸锂正极的本征性质出发,论述去钴化的可行性与无钴高镍正极的重点挑战,总结目前学界已有的实现策略,最后对无钴高镍正极的发展方向作出展望。

Co–MOFs纳米片/碳布复合材料的制备及在锂离子电池中的应用

采用液相沉积法在导电碳布表面原位生长Co-MOFs纳米片,制得了Co-MOFs/CF复合材料。通过红外光谱、X射线衍射、扫描电子显微镜、恒流充放电、循环伏安、电化学阻抗等手段对材料的组成、结构形貌和电化学性能进行了表征。结果表明:当用作无黏结剂型锂离子电池电极时,在50 mA/g电流密度下,Co-MOFs/CF的首次放电比容量为1 621.3 mA·h/g,100次循环后,其放电比容量仍可达445.1 mA·h/g。相比于纯Co-MOFs,Co-MOFs/CF的首次Coulomb效率和循环性能均有明显改善,主要归因于Co-MOFs的二维片状结构与碳布良好导电性之间的协同作用,Co-MOFs/CF优异的电化学性能使其成为很好的锂离子电池电极候选材料。

Ultrathin Al2O3-coated reduced graphene oxide membrane for stable lithium metal anode

Lithium （Li） metal has been considered as the most attractive anode materials for Li-ion batteries （LIBs） due to its high theoretic specific capacity. The formation of unstable solid electrolyte interphase （SEI） and dendritic Li on the metal anode, however, hindered its practical application. Herein, to address the issues, a Li-free electrode with ultrathin Al2O3 coated on reduced graphene oxide （rGO） membrane that covers a Cu foil current collector was developed. The composite electrode exhibits excellent interfacial protection of lithium metal deposited between Cu foil and rGO electrochemically. Firstly, it affords good Li^＋ permeability from the electrolyte. Secondly, the ultrathin Al2O3 has sufficient mechanical strength to inhibit the penetration of Li dendrite. Li metal was observed uniformly deposited between rGO membrane and Cu collector, and stable cycle performance of Li plating/stripping with Coulombic efficiency of ~ 91.75% at the lOOth cycle is achieved in organic carbonate electrolyte without any additives.