构建亲锂铜基3D集流体实现金属锂的均匀沉积

锂金属负极以其最高的理论比容量(3860 mAh·g ^-1)和最低的电化学电位(-3.04 V (vs SHE))被誉为电池界的“圣杯”。但是锂金属电池的缺点也尤为明显: 充放电过程中锂金属电池容易在负极不均匀沉积从而产生锂枝晶, 锂枝晶的产生会造成固体电解质介面(SEI)膜的持续破裂, 不稳定的SEI膜又会加剧锂枝晶的形成, 进而刺穿隔膜, 导致电池的循环性能下降, 产生安全隐患, 所以采取相应的措施在负极均匀沉积金属锂尤为重要。本研究使用商业化的铜网, 通过碱性溶剂的氧化和空气气氛煅烧, 在铜网表面形成均一的亲锂氧化铜纳米片阵列。铜网的3D结构可以有效减小电流密度, 亲锂的纳米片阵列可以降低锂的沉积过电势, 均匀沉积锂, 有效抑制锂枝晶的产生。在电流密度为3 mA·cm ^-2的半电池测试中, 稳定循环230圈后库伦效率稳定维持在99%以上; 搭配磷酸铁锂(LFP)全电池测试, 在1C(0.17 mA·mg ^-1)条件下可稳定循环300圈, 容量保持率为95%。本研究为锂金属负极3D集流体的设计提供了新思路。     

三维亲锂Cu@Sn纳米锥集流体用于无枝晶锂金属负极

锂在集流体上的不均匀沉积将导致严重的枝晶生长和体积膨胀等问题,传统的商业化泡沫铜集流体由于具有较大的体积和质量会降低电池的能量密度.本文通过简单的电沉积方法制备了体积小、重量轻,具有亲锂性的3D Cu@Sn纳米锥集流体.从成核与沉积的角度出发,纳米锥结构与亲锂的锡纳米颗粒的协同作用促进了锂的均匀沉积,可有效地抑制锂枝晶的生长.组装的半电池在1 mA cm^-2下经过100次循环后,库仑效率高达97.6%,锂对称电池在1 mA cm^-2下可以稳定循环600 h.将沉积金属锂后的Cu@Sn/Li复合负极与LiFePO₄组装的液态全电池在1 C倍率下, 550个循环之后,容量保持率为95.1%.此外, Cu@Sn纳米锥集流体在固态电池Li/Cu@Sn|PVDF–HFP–5 wt%Si O₂|LFP中也表现出优异的电化学性能,在1 C倍率下, 500个循环之后,放电容量未发生衰减.     

半限域层次孔炭三维锂负极的构筑及性能

金属锂负极是锂电池极具发展潜力的高能二次电池负极材料，但是锂枝晶生长、界面不稳定、循环稳定性差和体积膨胀大等问题限制了锂负极的应用。针对枝晶生长和体积膨胀的问题，本工作通过模板法构筑了一种具有较大比表面积的半限域式层次孔炭(HPC)材料，HPC电极材料的高比表面积可降低局部电流密度，丰富的孔道结构可将锂限制在其内部沉积，从而达到抑制枝晶生长和缓解体积膨胀的目的。Li‖HPC电池在电流密度为1.0 mA·cm^-2、沉积电量为1.0 mAh·cm^-2条件下可以循环超过250周次，其库仑效率保持在97.6%。采用此负极与磷酸铁锂(LiFePO₄)正极匹配制备的Li@HPC‖LiFePO₄全电池，在0.5 C下循环100周次后的正极放电比容量为93.6 mAh·g^-1,较相同条件下的Li@Cu‖LiFePO₄全电池(60.8 mAh·g^-1)提升了32.8 mAh·g^-1。     

人造固态电解质界面在锂金属负极保护中的应用研究EI北大核心CSCD

锂金属具有最低的氧化还原电位(-3.04V vs标准氢电极)和极高的比容量(3860mAh·g^-1),是理想的锂二次电池负极材料.然而电化学循环过程中,由于锂的不均匀成核生长,其表面产生锂枝晶,锂枝晶持续生长会刺穿隔膜,造成电池短路甚至引发火灾.因此需要对锂金属负极进行保护,抑制负面问题,发挥高性能.人造固态电解质界面技术是一种有效的锂金属负极保护策略,本质是预先在锂金属表面涂覆上保护层,保护层具有较高的离子传导性和电化学稳定性、较好的阻隔性和机械强度,可得到高效率、长寿命和无枝晶的锂金属负极.本文将近年来人造固态电解质界面在锂金属负极保护中的研究进展进行综述,对其制备方法、结构特点、锂金属负极循环性能、全电池电化学性能等方面作了详细介绍,分析当前存在问题并指出锂金属负极研究不仅需要加深机理研究还得与实际应用相结合.     

人造固态电解质界面在锂金属负极保护中的应用研究

锂金属具有最低的氧化还原电位(-3.04 V vs标准氢电极)和极高的比容量(3860 mAh·g~(-1)),是理想的锂二次电池负极材料。然而电化学循环过程中,由于锂的不均匀成核生长,其表面产生锂枝晶,锂枝晶持续生长会刺穿隔膜,造成电池短路甚至引发火灾。因此需要对锂金属负极进行保护,抑制负面问题,发挥高性能。人造固态电解质界面技术是一种有效的锂金属负极保护策略,本质是预先在锂金属表面涂覆上保护层,保护层具有较高的离子传导性和电化学稳定性、较好的阻隔性和机械强度,可得到高效率、长寿命和无枝晶的锂金属负极。本文将近年来人造固态电解质界面在锂金属负极保护中的研究进展进行综述,对其制备方法、结构特点、锂金属负极循环性能、全电池电化学性能等方面作了详细介绍,分析当前存在问题并指出锂金属负极研究不仅需要加深机理研究还得与实际应用相结合。     

半限域层次孔炭三维锂负极的构筑及性能EI北大核心

金属锂负极是锂电池极具发展潜力的高能二次电池负极材料,但是锂枝晶生长、界面不稳定、循环稳定性差和体积膨胀大等问题限制了锂负极的应用。针对枝晶生长和体积膨胀的问题,本工作通过模板法构筑了一种具有较大比表面积的半限域式层次孔炭(HPC)材料,HPC电极材料的高比表面积可降低局部电流密度,丰富的孔道结构可将锂限制在其内部沉积,从而达到抑制枝晶生长和缓解体积膨胀的目的。Li‖HPC电池在电流密度为1.0 mA·cm^(-2)、沉积电量为1.0 mAh·cm^(-2)条件下可以循环超过250周次,其库仑效率保持在97.6%。采用此负极与磷酸铁锂(LiFePO_(4))正极匹配制备的Li@HPC‖LiFePO_(4)全电池,在0.5 C下循环100周次后的正极放电比容量为93.6 mAh·g^(-1),较相同条件下的Li@Cu‖LiFePO_(4)全电池(60.8 mAh·g^(-1))提升了32.8 mAh·g^(-1)。     

金属锂负极的关键技术与研究进展

综述了近几年科研工作者基于金属锂负极本身的改性的最新研究进展。金属锂的理论质量比容量达3860 mAh/g,密度为0.534 g/cm^3,标准还原电位为-3.045 V,这些优势使得金属锂成为下一代理想的锂二次电池(如锂硫、锂空气电池等)的负极材料。然而,锂离子的不均匀沉积导致的锂枝晶生长、体积膨胀及其随之带来的电池安全隐患和循环寿命的降低等缺陷严重困扰着金属锂电池的发展。本文从机械地增加锂负极的表面积、锂合金负极及混合锂负极、锂负极表面层以及二维三维基底四个方面对金属锂负极的改性进行分析。最后提出要实现金属锂电池的产业化,应从解决锂枝晶和体积膨胀两个方面,通过结合不同改性方法进行研究探索。     

半限域层次孔炭三维锂负极的构筑及性能EI

金属锂负极是锂电池极具发展潜力的高能二次电池负极材料,但是锂枝晶生长、界面不稳定、循环稳定性差和体积膨胀大等问题限制了锂负极的应用。针对枝晶生长和体积膨胀的问题,本工作通过模板法构筑了一种具有较大比表面积的半限域式层次孔炭(HPC)材料,HPC电极材料的高比表面积可降低局部电流密度,丰富的孔道结构可将锂限制在其内部沉积,从而达到抑制枝晶生长和缓解体积膨胀的目的。Li‖HPC电池在电流密度为1.0 mA·cm^(-2)、沉积电量为1.0 mAh·cm^(-2)条件下可以循环超过250周次,其库仑效率保持在97.6%。采用此负极与磷酸铁锂(LiFePO_(4))正极匹配制备的Li@HPC‖LiFePO_(4)全电池,在0.5 C下循环100周次后的正极放电比容量为93.6 mAh·g^(-1),较相同条件下的Li@Cu‖LiFePO_(4)全电池(60.8 mAh·g^(-1))提升了32.8 mAh·g^(-1)。     

坚韧、弹性的氟化固体电解质界面稳定碳酸酯电解质中的锂金属（英文）

锂金属负极和碳酸酯类电解液之间不稳定的界面是限制高比能锂金属电池循环寿命的关键挑战.本文使用含苯环的双酚A乙氧基化物二甲基丙烯酸酯(BAED)交联剂调节聚(丙烯酸六氟丁酯)(PHFBA),设计了一种弹性人造固体电解质中间相(RASEI)来解决这个问题.刚性BAED分子可以对柔性PHBA基体进行调控,实现从600%伸长率到90%压缩率的卓越回弹性,并具有超过2 MPa的高杨氏模量.RASEI可以适应锂金属较大的体积变化,并确保电池运行过程中锂金属与RASEI之间的紧密接触,促进均匀的锂沉积并减少副反应.因此,经过RASEI修饰的Li‖Li对称电池可以在1 mA cm^-2和1 mAh cm^-2下实现超过500小时的长期循环.对循环后锂金属进行测试分析表明锂枝晶的生长得到了有效的抑制.此外,搭配20 mg cm^-2高阴极负载的NCM811软包电池在1 C下,经过200次循环后容量保持率超过85%.     

合金材料在锂金属负极中的应用研究进展

金属锂具有极低的电极电势及超高的比容量，是高比能锂二次电池的理想负极材料。然而，锂枝晶生长、体积膨胀效应及界面不稳定等问题限制了其商业化应用。通过合金负极、界面保护、负极结构设计及固态电解质等策略，可显著改善上述问题。锂合金材料具有高比容量、高离子电导率及良好亲锂性等特点，在上述策略中均扮演着重要角色。本文介绍合金材料的电化学性质，综述近年来合金材料在锂金属负极中的应用研究进展；最后梳理合金材料在锂金属负极中应用所面临的问题，并提出加强基础理论研究等建议。     

Progress on Lithium Dendrite Suppression Strategies from the Interior to Exterior by Hierarchical Structure Designs

Lithium (Li) metal is promising for high energy density batteries due to its low electrochemical potential (?3.04 V) and high specific capacity (3860 mAh g^?1). However, the safety issues impede the commercialization of Li anode batteries. In this work, research of hierarchical structure designs for Li anodes to suppress Li dendrite growth and alleviate volume expansion from the interior (by the 3D current collector and host matrix) to the exterior (by the artificial solid electrolyte interphase (SEI), protective layer, separator, and solid state electrolyte) is concluded. The basic principles for achieving Li dendrite and volume expansion free Li anode are summarized. Following these principles, 3D porous current collector and host matrix are designed to suppress the Li dendrite growth from the interior. Second, artificial SEI, the protective layer, and separator as well as solid‐state electrolyte are constructed to regulate the distribution of current and control the Li nucleation and deposition homogeneously for suppressing the Li dendrite growth from exterior of Li anode. Ultimately, this work puts forward that it is significant to combine the Li dendrite suppression strategies from the interior to exterior by 3D hierarchical structure designs and Li metal modification to achieve excellent cycling and safety performance of Li metal batteries.     

高性能自支撑CuS/SnS2锂电池负极材料

过渡金属硫化物作为锂电池负极材料具有极高比容量,但其制备的电极普遍存在导电性差、体积变化大等问题,本研究设计了一种新型的自支撑CuS/SnS₂镂空片状锂电池负极材料,以导电碳布作为基底,生长包覆CuS/SnS₂镂空纳米片,具备特殊的纳米包覆结构及双金属协同效应,使其在保持较高比容量的同时具备良好的循环稳定性,整体电化学性能优异。研究不同Cu/Sn含量对CuS/SnS₂负极材料电化学性能的影响,最佳配比的CuS/SnS₂负极材料在0.2 A·g?1电流密度下循环50次后比容量为1480 mAh·g?1,库伦效率稳定在99.5%,在2 A·g?1电流密度下循环200次后比容量仍能保持在697 mAh·g?1,库伦效率为99.8%。      

A carbon-based 3D current collector with surface protection for Li metal anode

Lithium metal is considered the ideal anode material for Li-ion-based batteries because it exhibits the highest specific capacity and lowest redox potential for this type of cells.However,growth of Li dendrites,unstable solid electrolyte interphases,low Coulombic efficiencies,and safety hazards have significantly hindered the practical application of metallic Li anodes.Herein,we propose a three-dimensional (3D) carbon nanotube sponge (CNTS) as a Li deposition host.The high specific surface area of the CNTS enables homogenous charge distribution for Li nucleation and minimizes the effective current density to overcome dendrite growth.An additional conformal A12O3 layer on the CNTS coated by atomic layer deposition (ALD) robustly protects the Li metal electrode/electrolyte interface due to the good chemical stability and high mechanical strength of the layer.The Li@ALD-CNTS electrode exhibits stable voltage profiles with a small overpotential ranging from 16 to 30 mV over 100 h of cycling at 1.0 mA·cm-2.Moreover,the electrodes display a dendrite-free morphology after cycling and a Coulombic efficiency of 92.4％ over 80 cycles at 1.0 mA·cm-2 in an organic carbonate electrolyte,thus demonstrating electrochemical stability superior to that of planar current collectors.Our results provide an important strategy for the rational design of current collectors to obtain stable Li metal anodes.     

Lithiophilic Cu‐CuO‐Ni Hybrid Structure: Advanced Current Collectors Toward Stable Lithium Metal Anodes

Metallic lithium (Li) is a promising anode material for next‐generation rechargeable batteries. However, the dendrite growth of Li and repeated formation of solid electrolyte interface during Li plating and stripping result in low Coulombic efficiency, internal short circuits, and capacity decay, hampering its practical application. In the development of stable Li metal anode, the current collector is recognized as a critical component to regulate Li plating. In this work, a lithiophilic Cu‐CuO‐Ni hybrid structure is synthesized as a current collector for Li metal anodes. The low overpotential of CuO for Li nucleation and the uniform Li⁺ ion flux induced by the formation of Cu nanowire arrays enable effective suppression of the growth of Li dendrites. Moreover, the surface Cu layer can act as a protective layer to enhance structural durability of the hybrid structure in long‐term running. As a result, the Cu‐CuO‐Ni hybrid structure achieves a Coulombic efficiency above 95% for more than 250 cycles at a current density of 1 mA cm^?2 and 580 h (290 cycles) stable repeated Li plating and stripping in a symmetric cell.     

Bi/3DPG composite structure optimization realizes high specific capacity and rapid sodium-ion storage

As an anode material for sodium-ion batteries (SIBs), bismuth (Bi) has attracted widespread attention due to its suitable voltage platform and high volumetric energy density. However, the severe volume expansion of Bi during charging and discharging leads to a rapid decline in battery capacity. Loading Bi on the graphene can relieve volume expansion and improve electrochemical performance. However, excessive loading of Bi on graphene will cause the porosity of the composite material to decrease, which leads to a decrease of the Na⁺ transmission rate. Herein, the Bi/three-dimensional porous graphene (Bi/3DPG) composite material was prepared and the pore structure was optimized to obtain the medium-load Bi/3DPG (Bi/3DPG-M) with better electrochemical performance. Bi/3DPG-M exhibited a fast kinetic process while maintaining a high specific capacity. The specific capacity still remained at 270 mA·h·g⁻¹ (93.3%) after 500 cycles at a current density of 0.1 A·g⁻¹. Even at 5 A·g⁻¹, the specific capacity of Bi/3DPG-M could still reach 266.1 mA·h·g⁻¹. This work can provide a reference for research on the use of alloy–graphene composite in the anode of SIBs.     

Dual‐Function,Tunable, Nitrogen‐Doped Carbon for High‐Performance Li Metal–Sulfur Full Cell

Lithium metal–sulfur (Li–S) batteries are attracting broad interest because of their high capacity. However, the batteries experience the polysulfide shuttle effect in cathode and dendrite growth in the Li metal anode. Herein, a bifunctional and tunable mesoporous carbon sphere (MCS) that simultaneously boosts the performance of the sulfur cathode and the Li anode is designed. The MCS homogenizes the flux of Li ions and inhibits the growth of Li dendrites due to its honeycomb structure with high surface area and abundance of nitrogen sites. The Li@MCS cell exhibits a small overpotential of 29 mV and long cycling performance of 350 h under the current density of 1 mA cm^‐2. Upon covering one layer of amorphous carbon on the MCS (CMCS), an individual carbon cage is able to encapsulate sulfur inside and reduce the polysulfide shuttle, which improves the cycling stability of the Li–S battery. As a result, the S@CMCS has a maximum capacity of 411 mAh g^‐1 for 200 cycles at a current density of 3350 mA g^‐1. Based on the excellent performance, the full Li–S cell assembled with Li@MCS anode and S@CMCS cathode shows much higher capacity than a cell assembled with Li@Cu anode and S@CMCS cathode.     

Directing Highly Ordered and Dense Li Deposition to Achieve Stable Li Metal Batteries

Li metal anode is promising to achieve high-energy-density battery. However, it has rapid capacity fading due to the generation of inactive Li (dead Li), especially at high current density. This study reveals that the random distribution of Li nuclei leads to large uncertainty for the further growth behavior on Cu foil. Here, periodical regulation of Li nucleation sites on Cu foil by ordered lithiophilic micro-grooves is proposed to precisely manipulate the Li deposition morphology. The management of Li deposits in the lithiophilic grooves can induce high pressure on the Li particles, leading to the formation of dense Li structure and smooth surface without dendrite growth. Li deposits comprising tightly packed large Li particles largely reduce the side reaction and the generation of isolated metallic Li at high current density. Less dead Li accumulating on the substrate significantly prolongs the cycling life of full cells with limited Li inventory. The precise manipulation of the Li deposition on Cu is promising for high-energy and stable Li metal batteries.