IF 13.6 | CAS & USTC,China | 双梯度结构电极设计实现LIB安全极快充

文摘   2024-11-03 08:30   新加坡  
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 1. 原文链接

DOI Link:

https://www.science.org/doi/10.1126/sciadv.abm6624

 2.通讯作
  • Googleshcolar

https://scholar.google.com/citations?user=pcQ8ebEAAAAJ&hl=en&oi=sra

https://scholar.google.com/citations?user=s8m2_tsAAAAJ&hl=en&oi=sra

https://scholar.google.com/citations?user=Sxty8TMAAAAJ&hl=en&oi=sra

  • ScienceDirect: 
https://www.sciencedirect.com/author/7405731967/shuhong-yu
https://www.scopus.com/authid/detail.uri?authorId=16836857400
https://www.scopus.com/authid/detail.uri?authorId=35172323200
  • UniversityWeb:
https://faculty.ustc.edu.cn/yushuhong/zh_CN/index.htm
https://faculty.ustc.edu.cn/niyong/en/index.htm

https://www.hfnl.ustc.edu.cn/detail?id=11471

 3. 收录日期

Received: 3 Oct. 2021

Accepted: 10 Mar. 2022
Published: 27 April 2022
 4. 研究内容

1. 科学问题

  • 低的孔隙率石墨负极在快充时的极化效应导致电极表面形成锂金属沉积。
  • 通过优化微结构减少Li⁺浓度极化,降低极化效应

2. 实验与模型方法

2.1 实验方法 

1. CuNWs和G@Cu颗粒的合成

  • CuNWs合成通过Cu²⁺在碱性溶液中的化学还原制得,将NaOH、Cu(NO₃)₂、乙二胺和联氨混合,加热至80℃并搅拌80分钟,离心洗涤后将CuNWs储存在乙醇中(4℃)。

  • G@Cu颗粒合成:

    • 石墨颗粒表面改性:通过铬酸水溶液对石墨颗粒氧化30分钟;用SnCl₂溶液处理30分钟,再用PdCl₂溶液对石墨颗粒表面还原Pd²⁺,制得Pd修饰石墨粉末。

    • 铜自催化镀覆:将Pd修饰石墨粉末加入Cu²⁺溶液中,加入NaOH和甲醛以还原铜,形成G@Cu颗粒。最后干燥备用。

2. 双梯度G@Cu-CuNWs负极的制备

  • G@Cu-CuNWs复合材料制备:将G@Cu和CuNWs悬浮液倒入不锈钢模具中,乙醇挥发后形成复合膜,随后在450℃氢气/氩气气氛下退火4小时,得到密集梯度结构的G@Cu-CuNWs负极。

  • 厚负极制备:增加悬浮液至69 ml,保持其他条件不变以制备更厚的电极。

3. CuNWs、G@Cu和G@Cu-CuNWs的表征

  • 形貌观察:使用SEM观察CuNWs、G@Cu及其截面形貌,样品截面通过Ar离子束切割并镀Pt保护层。

  • 成分分析:使用XRD分析Cu纳米颗粒在石墨颗粒上的覆盖,TGA测量G@Cu颗粒中Cu的含量。

  • 导电性测试:四探针测试电极导电性;通过SEM测量厚度并计算密度。

4. 石墨负极的电化学性能评估

  • 半电池测试:

    • 石墨电极与锂金属对电,进行循环伏安测试和电化学阻抗谱测试,初始循环在0.05 C进行。

    • 倍率性能:以不同倍率放电并以0.2 C充电,每个倍率循环4次。

  • 对称电池测试:

    • 石墨电极与锂化石墨(LiG)对电,评估石墨的锂嵌入速率能力,放电倍率为0.2 C。

  • 全电池测试:

    • 与LiCoO₂(LCO)正极组装,电压范围2.5至4.3 V,测试循环及快速充电性能。

2.2 模拟方法
1. 模型选择:
    • 使用粒子级理论模型模拟电极的充电过程,假设电极具有恒定的平均孔隙率和总体积。

    • 与伪二维(P2D)Newman模型相比,粒子级模型能够直接研究孔隙率的空间分布和不同粒径颗粒对锂电池性能的影响。
    2. 模拟重点:
      • 主要关注电解液中的浓度极化和颗粒的利用率

      • 模型假设电极由不同尺寸的颗粒组成,孔隙中完全填充电解液,并忽略添加剂和颗粒表面固体电解质界面的形成。
      3. 石墨颗粒的各向异性扩散:
        • 石墨颗粒的层状结构显著影响扩散过程,锂在层状平面内的扩散速度远高于层状平面间的扩散速度,故需考虑各向异性扩散行为。
        4. 模型细节:
          • 电极由n个石墨颗粒组成,引入域参数Ψp(p=1, 2, …, n)表征第p个颗粒的方向和位置,其中Ψp在颗粒内为1,颗粒外为0,颗粒表面则平滑过渡。

          • 通过菲克定律描述第p个颗粒内的锂扩散

          3. 研究结果

          3.1 电极结构的优化

          1. 粒子级理论模型用于优化厚电极结构 (Fig. 1A)

          • 高孔隙率能提升厚电极传输能力,但会降低能量密度;模型需优化不同尺寸颗粒和孔隙率分布以实现厚电极快速充电。
          • 模拟假设厚电极内的孔隙和颗粒沿电流收集体平面随机分布,并在垂直于电流收集体的方向上不均匀分布。
          • 模型选择包含多种石墨颗粒的代表性立方体体积来模拟整个电极。

          2. 孔隙率和颗粒尺寸分布设计 (Fig. 1B-D)

          • 在固定孔隙率(35%)的厚电极中,初步构建顶部孔隙率高、底部低的单一梯度结构,并与孔隙率随机分布的电极(随机型)进行对比。

          • 孔隙率和颗粒尺寸的厚度方向分布,模拟设定充电电流密度为3.75 mA cm−2,以便考察该结构在快速充电条件下的性能。

          3. 单一梯度与双梯度结构充电性能对比 (Fig. 1E)

          • 当电极充至截止电压(0 V vs. Li+/Li)时,单一梯度结构相比随机型展现出更高的活性材料利用率和更低的过电位,但改进效果仍有限

          • 为进一步提升充电性能,在单一梯度结构基础上引入颗粒尺寸梯度分布,构建双梯度结构。

          • 设计了ST型(顶部小颗粒)和BT型(顶部大颗粒)两种双梯度结构,其中ST型显著提高了快速充电性能,而BT型的充电性能不如单一梯度结构。

          4. 双梯度结构的Li+浓度分布特性 (Fig. 1F)

          • 在充电至截止电压(3.75 mA cm−2)时,ST双梯度结构的液相Li+浓度分布比其他类型电极平滑,表现出明显减小的Li+浓度极化,从而降低了整体过电位

          • 其他类型电极在厚度方向上从顶部到底部的Li+浓度极化较为剧烈,影响了充电性能。

          5. Li+浓度分布改善的物理机制 (Fig. 2A)

          • ST双梯度结构中,高孔隙率的顶部区域提高了局部的有效扩散系数,有利于Li+自顶部向下扩散,使顶部的Li+浓度低于均匀分布的随机型电极。

          • 在充电后期,位于顶部的小颗粒更容易被完全锂化,减少了顶部的电化学反应速率,降低了顶部的Li+消耗,使更多的Li+到达底部。

          6. 高电流密度下的活性材料利用率 (Fig. 2B)

          • 与随机型和单一梯度电极相比,双梯度电极在高电流密度下保留了更高的活性材料利用率,表现出优异的快速充电性能。
          Fig. 1. Model illustration of the random type, the single-gradient type and the dual-gradient type electrode structure and simulated charging process in different electrode structures. (A) Illustration of the representative volume in the electrode. (B) Spatial distribution of the electrode particles with different sizes and porosity in different electrode models. (C) The porosity distribution and (D) the particle size distribution along the thickness direction, respectively. L indicates the distance to the bottom of electrode along the thickness direction. The electrode is evenly divided into five parts along the thickness direction and the average porosity of each part is calculated. (E) Simulated voltage versus state of charge (SOC) curves of different type electrodes under the current density of 3.5 mA/cm2. The values of overpotential (ΔV) are calculated by taking the potential difference between the cut-off voltage at fast rates versus corresponding Li+ potential at open circuit. The potential at open circuit is as close as possible to the thermodynamic equilibrium. (F) Simulated charging process in BT-dual-gradient type electrode. (G) The ΔV at different charging current densities.
          Fig. 2. Concentration polarization analysis in different electrode structures and the simulated graphite particle utilization at different current densities.

          3.2 电双梯度结构石墨电极

          1. 双梯度结构石墨电极的制备工艺 (Fig. 3A)

          • 传统工艺因所用浆料高粘度(0.15 Pa·s)难以制备双梯度结构。

          • 开发了一种低粘度(1.75 × 10⁻³ Pa·s)无聚合物粘结剂的浆料以实现该结构

          • 铜涂层石墨颗粒(G@Cu)和铜纳米线(CuNWs)通过溶液法制备,并确认其形貌均匀,表面涂层良好 (Fig. 3, C to F)

          • 将G@Cu颗粒和CuNWs分散于乙醇中形成浆料,倒入模具中。乙醇蒸发过程中,因沉降速度不同,CuNWs和G@Cu颗粒逐层自上而下从大到小排序。

          • 蒸发后形成由G@Cu颗粒和CuNWs互连的薄膜 (Fig. 3G),经过退火和压延,得到尺寸为4×10 cm的致密电极(Fig. 3A)

          2. 双梯度电极的结构特性 (Fig. 4, A and B)

          • 电极顶部和底部表面颜色差异表明CuNWs和小G@Cu颗粒分布在电极顶部,而大G@Cu颗粒集中在底部。

          • 通过扫描电镜(SEM)图像观察到,电极截面内石墨颗粒尺寸从顶部的约15 μm递增至底部的35 μm (Fig. 4C)

          3. 铜纳米线网络和元素分布分析 (Fig. 5A-D)

          • 局部SEM图像及元素映射显示,CuNWs在石墨颗粒间形成连接网络,CuNWs含量自电极顶部向底部递减。

          • 该分布验证了G@Cu颗粒和CuNWs在电极中呈现梯度分布特性。

          4. 电极中铜含量及结构稳定性 (Fig. 4, D and E)

          • 热重分析(TGA):表明电极中电化学惰性铜的质量含量为14.13%,显著低于商用石墨电极(30%~40%,Table S1)。

          • G@Cu-CuNWs石墨负极的线点接触提高了导电性和柔韧性,优于碳黑点对点接触的商用石墨负极 (Fig. 4, F and I)

          5. 浆料滚压过程中的电极结构稳定性 (Fig. 6, A to C)

          • 传统聚合物浆料制备的厚石墨负极在滚压后易从铜箔集流体上脱落,而G@Cu-CuNWs厚电极则保持集成性。

          • 随着滚压过程的逐步进行,电极厚度从311 μm减小到243 μm,再减小到198 μm (Fig. 6, D to F),同时压实密度从0.91 g/cm³增加到1.16 g/cm³,最终达到1.43 g/cm³ (Fig. 6G)

          6. 三维互联网络结构的优越性 (Fig. 6G)

          • 双梯度结构使粒径分布和孔隙率逐层变化,形成紧密结构的互联网络电极。

          • 制备出的3D网络电极展现了厚石墨负极在结构设计和制造方面的优势,提升了快速充电性能和结构稳定性。

          Fig. 3. The preparation illustration of the dual graident electrode and the corresponding characterizations of the slurry, CuNWs, G@Cu particles. (A) The formation schematic of dual gradient structure in the G@Cu-CuNWs anode. Inset is the optical photograph of the prepared freestanding G@Cu-CuNWs electrode. (B) The viscosity curves of differnt slurries for the electrode preparation, indicating much lower viscosity of our G@Cu-CuNWs slurry in comparion to traditional graphite anode slurry. (C-E) SEM image of CuNWs (C), graphite particles (D) and G@Cu particles (E), respectivley. (F) SEM image and corresponding elementary mapping (carbon and copper) of the G@Cu particle.


          Fig. 4. The characterization of G@Cu-CuNWs membrane before calendering. (A, B) The top (A) and bottom surface (B) SEM image of G@Cu-CuNWs membrane, respectively. (C) The particle size distribution of G@Cu particles in the G@Cu-CuNWs electrode along the thickness direction. (D) Powder X-ray diffraction patterns of the grahite and G@Cu particles. (E) Thermal gravimetric analysis (TGA) curves of the grahite particles and G@Cu-CuNWs membrane. The calculated Cu content of G@Cu is 14.7%. After the heating process in TGA test, the graphite was burnt out and Cu was oxidized to copper oxide. According to the left content of copper oxide, the Cu content in the G@Cu-CuNWs can be calculated. (F) The cross-sectional SEM image of the G@Cu-CuNWs membrane after annealing at 450 oC for 2 hours under H2/Ar (5%/95%) atmosphere. (G) The corresponding magnified SEM image of G@Cu-CuNWs membrane. (H, I) Optical photograph of the areal resistance test of commercial graphite anode (H) and G@Cu-CuNWs anode (I). The M-3 Mini type four-probe tester shows that the areal resistance of the G@Cu-CuNWs anode (65.0 Ω) is lower than that of commercial graphite anode (87.9 Ω).

          Fig. 5. The microstructure characterization and the electrochemical performance evaluation of thick dual-gradient G@Cu-CuNWs anode and random graphite anode.

          Fig. 6. Roll pressing of the electrode. (A) Optical photograph of the thick tranditional graphite electrode on the copper current collectors after the roll pressing. (B) Optical photograph of current collector free thick graphite anode. (C) Optical photograph of the thick G@Cu-CuNWs anode after the roll pressing. (D-F) The cross-sectional SEM image of the G@Cu-CuNWs electrode rolled by 280 μm (D), 230 μm (E), 180 μm (F) spacing, respectivley. The thickness of the electrode was measured as 311 μm (D), 243 μm (E) and 198 μm (F), respectively. (G) The corresponding curve of electrode thickness versus compaction density

          3.3 评估双梯度结构在提升快速充电性能中的作用

          1.1 电化学性能评估 (Fig. 7A-F)

          • 首次循环的充放电性能厚G@Cu-CuNWs电极和随机结构石墨电极均表现出正常的充放电电压曲线,库仑效率分别为91%和89.2%,但G@Cu-CuNWs电极极化更低 (Fig. 7A)

          • 不同倍率的充放电性能:在不同倍率下,G@Cu-CuNWs电极的极化低于石墨电极 (Fig. 7B)

          • 循环伏安测试:G@Cu-CuNWs电极显示出较小的氧化还原峰位置和更大的峰电流,进一步表明其极化较低且反应动力学提升(Fig. 7C)

          • 循环稳定性:G@Cu-CuNWs电极的循环稳定性显著优于随机石墨电极 (Fig. 7D)

          1.2 充电倍率性能测试 (Fig. 7E-F)

          • 充电电压曲线:在对称电池测试中,G@Cu-CuNWs电极在恒流充电阶段表现出更低的充电电压平台和更高的荷电状态(SOC),相较于随机石墨电极更具优势 (Fig. 7E)

          • 倍率循环测试:在不同倍率下,G@Cu-CuNWs电极在恒流充电阶段的SOC高于石墨电极(0.5 C和1 C时分别为76%和48%,石墨电极分别为51%和32%),表明双梯度结构G@Cu-CuNWs电极具有低极化和快速充电能力 (Fig. 7F)

          1.3 机理分析:三维结构重建与参数提取 (Fig. 5E, Fig. 8)

          • 3D结构重建:通过实验室X射线断层扫描获取厚G@Cu-CuNWs电极的三维重建结构,从重建模型中提取体素(50 μm × 50 μm × 150 μm),包含颗粒尺寸和位置信息,以此作为颗粒级模型的输入 (Fig. 8)

          1.4 孔隙率和离子分布比较 ·

          • 孔隙率分布:G@Cu-CuNWs电极的孔隙率沿厚度方向呈线性梯度分布,而石墨电极孔隙率均匀分布,两者的总孔隙率相似(G@Cu-CuNWs为33.4%,石墨为34.2%) (Fig. S7A)。

          • 锂离子分布:在相同电流密度下(5 mA cm⁻²),G@Cu-CuNWs电极的Li⁺离子分布更均匀,表明双梯度结构显著提升了电极中Li⁺的传输能力,减轻了浓度极化 (Fig. 5E, Fig. 9B)

          1.5 活性材料利用率与电压极化 (Fig. 5F-G)

          • 活性材料利用率:G@Cu-CuNWs电极的活性材料利用率明显高于随机石墨电极 (Fig. 5F)

          • 电压极化与荷电状态:在截止电压下,G@Cu-CuNWs电极的电压极化更低,SOC更高,证明其充电性能优于石墨电极 (Fig. 5G)

          Fig. 7.  Electrochemical performance comparison of thick G@Cu-CuNWs and graphite anodes.  (A) Initial discharge/charge voltage profiles of the G@Cu-CuNWs and graphite anode in the half cell at the rate of 0.1 C (1 C=370 mA g-1).  (B) The charge/discharge voltage profiles of the thick G@CuCuNWs and graphite anode at different rates.  (C) CV curves of the thick G@Cu-CuNWs and graphite anode in the first four cycles.  Scan rate: 0.1 mV s-1.  The reduced polarization and enhanced peak current indicate the excellent reaction kinetics in our dual-gradient structural anode.  (D) The cycling performance of the G@Cu-CuNWs and graphite anode over 50 cycles at 0.1 C. (E) The curves of charge voltage versus state of charge (SOC) in the symmetric cell at different charging rates.  (F) The rate performance comparison in the symmetric cell.

          Fig. 8. 3D reconstruction of the G@Cu-CuNWs and randon graphite anode. a, b, Threedimensional volume rendering of the G@Cu-CuNWs (A) and graphite (B) anode, respectively. A multi-level image threshold method was employed to distinguish the void space (gray scale intensity 0) from other solid materials (gray scale intensity 255). For visual depiction, the binary images are recolored with bule-green (solid materials) and gray (pores). (C, D) The longitudinal cross-sections of the G@Cu-CuNWs (C) and graphite (D) anode, respectively. (E, F) The pore structure extraction from the inside electrode of G@Cu-CuNWs (E) and graphite (F), respectively.

          Fig. 9. The porosity and caculated Li+ ion concentration distribution comparison of G@CuCuNWs and graphite anode along the thickness direction. (A) The porosity distribution analysis along the thickness direction in the G@Cu-CuNWs and graphite anode. (B) The caculated Li+ ion concentration distribution in the dual gradient G@Cu-CuNWs and random graphite anode along the thickness direction.

          3.4 超快充性能评估

          1. 超快速充电性能评估的双梯度结构电极

          1.1 薄电极的电化学性能 (Fig. 10A-C)

          • 电极制备:制备相对薄的G@Cu-CuNWs电极(约70 μm),评估其电化学性能,面积容量约为3 mAh cm⁻²。

          • 对称电池测试:使用锂化石墨作为对电极,G@Cu-CuNWs电极在恒流充电阶段显示出比随机石墨电极更低的充电电压平台和更高的荷电状态(SOC) (Fig. 10A)

          • 倍率性能:G@Cu-CuNWs电极的倍率性能优于随机石墨电极 (Fig. 10B)

          • 充电能力:在6 C时,G@Cu-CuNWs电极的SOC可达约60%,意味着在10分钟内可充电60% (Fig. 10C)

          1.2 半电池与全电池性能比较 (Fig. 11)

          • 充电性能:在使用锂箔作为对电极的半电池中,G@Cu-CuNWs电极表现出更高的充电容量、较低的过电位以及在1 C下更稳定的循环性能。

          • 与其他结构设计比较与其他梯度结构设计(无梯度和相反梯度)进行比较,结果确认改善的充电性能主要源于新结构而非其物理特性 (Fig. 12)

          2. 双梯度结构全电池性能测试 (Fig. 13D-E)

          2.1 全电池激活与充电测试

          • 激活循环:在0.1 C时,双梯度G@Cu-CuNWs和随机石墨基全电池的面积容量均为约3 mAh cm⁻² (Fig. 13A)

          • 充电性能:在3 C充电时,使用双梯度G@Cu-CuNWs电极的全电池显示出更低的充电过电位,达到1.92 mAh cm⁻²的充电容量,而随机石墨电极仅为0.63 mAh cm⁻² (Fig. 10D)

          2.2 高倍率充电与稳定性 (Fig. 10E)

          • 6 C充电测试:使用双梯度G@Cu-CuNWs电极的全电池在恒流充电阶段可以达到0.82 mAh cm⁻²的充电容量,而随机石墨电极仅为0.18 mAh cm⁻² (Fig. 13E)

          • 循环稳定性:双梯度G@Cu-CuNWs电极在1 C和3 C充电速率下表现出更好的循环稳定性 (Fig. 13B-C)

          3. 充电时间与SOC关系 (Fig. 13F)

          3.1 充电时间缩短

          • 充电效率由于双梯度结构带来的极化效应减少,使用双梯度G@Cu-CuNWs电极的全电池在3 C下充电60%和80%的时间分别为9.6和15.1分钟,而随机石墨电极分别为14.2和24.1分钟(Fig. 16)

          • 6 C充电性能:在6 C充电时,双梯度G@Cu-CuNWs电极的60%和80%充电时间分别为5.6和11.4分钟,远低于随机石墨电极的12.4和23.8分钟。

          4. 与其他石墨电极比较 (Fig. 14A-B)

          4.1 速率性能比较

          • 速率性能比较:将所制备的双梯度G@Cu-CuNWs电极与之前报道的石墨电极进行比较,结果表明,即使在6 C时,双梯度G@Cu-CuNWs电极仍能保持1.99 mAh cm⁻²的面积容量,展现其超快速充电能力 (Fig. 14A)

          4.2 能量密度评估

          • 能量密度:双梯度电极结构在高倍率下也赋予了全电池高体积能量密度,在6 C充电速率下能量密度达到700 Wh liter⁻¹,而随机石墨电池为550 Wh liter⁻¹(Fig. 14B)

          5. 大型电池应用前景

          5.1 机械性能测试 (Fig. 15)

          • 杨氏模量测试:浸泡在电解液中的G@Cu-CuNWs电极的杨氏模量为215.2 MPa,与无铜箔的石墨电极(189.6 MPa)相近,但远低于带铜箔的石墨电极。

          • 未来发展:由于缺乏电流收集器,G@Cu-CuNWs电极的应用在组装和测试过程受到限制,开发无标签电极的袋式电池将是未来G@Cu-NWs电极应用的有效策略。
          Fig. 10. The fast-charging performance evaluation of the G@Cu-CuNWs anode for practical full cells.

          Fig. 11. Electrochemical performance evalution of 70 μm thick G@Cu-CuNWs and graphite anode in the half cell. (A) The rate performance of the G@Cu-CuNWs and graphite anode in the half cell using the Li foil as the counter electrode. (B) The cycling performance of the G@Cu-CuNWs and graphite anode at 1 C. (C, D) Voltage profiles (C) during charging process of the G@Cu-CuNWs and graphite anode with increasing the charing rate from 0.5 to 5 C and the corresponding overpotential comparison. (D). (E) The plots of SOC at galvanostatic state versus the cycle number of the G@CuCuNWs and graphite anode with the rate increasing from 1 to 5 C. (F) The comparsion of SOC at galvanostatic stage of the G@Cu-CuNWs and graphite anode at different rates.

          Fig. 12. The constant current charging ratio of G@Cu-CuNWs electrode with other types of gradient structrue at 1C.
          Fig. 13. Electrochemical performance evaluation of the G@Cu-CuNWs and random graphite anode in the full cell coupled with the LCO cathode. (A) The first charge/discharge voltage profiles of the G@Cu-CuNWs‖LCO and graphite‖LCO full cells. (B, C) Cycling performance of the full cells in the voltage range from 3 to 4.3 V for 50 cycles under 1 C (B) and 3 C (C) (1 C = 370 mA g-1), respectively. The discharging rate was fixed at 0.5 C in all cycling tests. (D, E) The curves of voltage and SOC versus the charge time at the rate of 3 C (D) and 6 C (E), respectively. The required time for any SOC can be extracted from these curves.
          Fig. 14. The comparison of charging rate performance and energy density of dual-gradient G@Cu-CuNWs with previously reported graphite anodes.

          Fig. 15. Stress−strain curves of G@Cu-CuNWs and Graphite anode without Cu foil.

          Fig. 16. The electrochemial performance comparison of the random structured G@Cu-CuNWs and dual gradient structured G@Cu-CuNWs anode. (A-C) The comparison of electrochemical performance in the symmetric cell. (A, B) The charge voltage profiles at the different charging rate of 3 C (A) and 6 C (B), respectively. (C) The corresponding histogram of SOC in galvanostatic charging process at different C-rate. (D-F) The comparison of electrochemical performance in the full cell. (D,E) The charge voltage profiles at the different charging rate of 3 C (D) and 6 C (E), respectively. (F) The corresponding histogram of SOC in the galvanostatic charging process at the different C-rate.

          4. 重要结论

          • 无聚合物粘合剂浆料技术:一种新型的无聚合物粘合剂的浆料技术,以制造双梯度结构的G@Cu-CuNWs电极。

          • 快速充电能力:实现在厚G@Cu-CuNWs电极(≥9 mAh cm⁻²)和工业级G@Cu-CuNWs电极(约3 mAh cm⁻²)上的快速充电。

          • 高能量密度与快速充电结合:使用G@Cu-CuNWs电极的全电池能够在6 C下快速充电,充电60%仅需5.6分钟,80%仅需11.4分钟。

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