An Endotenon Sheath-Inspired Double-Network Binder Enables Superior Cycling Performance of Silicon Electrodes

Silicon(Si)has been regarded as an alternative anode material to traditional graphite owing to its higher theoretical capacity(4200 vs.372 m Ah g;).However,Si anodes suffer from the inherent volume expansion and unstable solid electrolyte interphase,thus experiencing fast capacity decay,which hinders their commercial application.To address this,herein,an endotenon sheathinspired water-soluble double-network binder(DNB)is presented for resolving the bottleneck of Si anodes.The as-developed binder shows excellent adhesion,high mechanical properties,and a considerable self-healing capability mainly benefited by its supramolecular hybrid network.Apart from these advantages,this binder also induces a Li;N/Li F-rich solid electrolyte interface layer,contributing to a superior cycle stability of Si electrodes.As expected,the DNB can achieve mechanically more stable Si electrodes than traditional polyacrylic acid and pectin binders.As a result,DNB delivers superior electrochemical performance ofSi/Li half cells and Li Ni;Co;Mn;O;/Si full cells,even with a high loading of Si electrode,to traditional polyacrylic acid and pectin binders.The bioinspired binder design provides a promising route to achieve long-life Si anode-assembled lithium batteries.

Engineering and Optimization of Silicon–Iron–Manganese Nanoalloy Electrode for Enhanced Lithium-Ion Battery

The electrochemical performance of a battery is considered to be primarily dependent on the electrode material. However, engineering and optimization of electrodes also play a crucial role, and the same electrode material can be designed to offer significantly improved batteries. In this work, Si–Fe–Mn nanomaterial alloy(Si/alloy) and graphite composite electrodes were densified at different calendering conditions of 3, 5, and 8 tons, and its influence on electrode porosity, electrolyte wettability, and long-term cycling was investigated. The active material loading was maintained very high(~2 mg cm^(-2)) to implement electrode engineering close to commercial loading scales. The densification was optimized to balance between the electrode thickness and wettability to enable the best electrochemical properties of the Si/alloy anodes.In this case, engineering and optimizing the Si/alloy composite electrodes to 3 ton calendering(electrode densification from 0.39 to 0.48 g cm^(-3)) showed enhanced cycling stability with a high capacity retention of ~100% over 100 cycles.

Silicon micropillar electrodes of lithiumion batteries used for characterizing electrolyte additives

The 100 crystal-oriented silicon micropillar array platforms were prepared by microfabrication processes for the purpose of electrolyte additive identification. The silicon micropillar array platform was used for the study of fluorinated vinyl carbonate(FEC), vinyl ethylene carbonate(VEC), ethylene sulfite(ES), and vinyl carbonate(VC) electrolyte additives in the LiPF_6 dissolved in a mixture of ethylene carbonate and diethyl carbonate electrolyte system using charge/discharge cycles, electrochemical impedance spectroscopy, cyclic voltammetry, scanning electron microscopy, and x-ray photoelectron spectroscopy. The results show that the silicon pillar morphology displays cross-shaped expansion after lithiation/delithiation, the inorganic lithium salt keeps the silicon pillar morphology intact, and the organic lithium salt content promotes a rougher silicon pillar surface. The presence of poly-(VC) components on the surface of FEC and VC electrodes allows the silicon pillar to accommodate greater volume expansion while remaining intact. This work provides a standard, fast, and effective test method for the performance analysis of electrolyte additives and provides guidance for the development of new electrolyte additives.

Electrochemical behavior of insulin on pretreated carbon black electrode enhanced with silicon carbide nanostructure

We previously reported the direct electrochemical detection of insulin at bare carbon electrodes. Here a novel modified acetylene carbon black paste electrode(SiC/CB-CPE), based on the outstanding characteristics of silicon carbide nanostructure,was developed for the electrooxidation of insulin in alkaline solution and it was characterized by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) in 5 mmol/L Fe(CN)63-/4- solution. It is found that silicon carbide nanostructure doped into the CB-CPE greatly facilitates the redox electrochemistry of Fe(CN)63-/4- probe and the electrochemical oxidation of insulin. The electrooxidation of insulin is a one-electron and one-proton reaction and an irreversible adsorption-controlled electrode process. The anodic oxidation current increases linearly with the concentration of insulin from 1×10-7mol/L to1.2×10-6mol/L in 0.1 mol/L Na2CO3-NaHCO3 buffer solution(pH 10.0) and the detection limit was 50 nmol/L. In addition, the SiC/CB-CPE shows good sensitivity, reproducibility, renewability and capacity of resisting disturbance.

Sulphur-template method for facile manufacturing porous silicon electrodes with enhanced electrochemical performance

Sulphur(S)-template method based on conventional slurry-casting method has been developed to pro-duce porous silicon(Si)electrodes.The facile fabrication technology is suitable for current production line and expected to be widely applied to various electrode materials under large volume change during operation.Specifically,S particles as template agent are mixed with active material Si,carbon conductor and binder forming uniform slurry.After casting and drying,the electrodes are immersed in carbon disul-fide solution to remove S particles rapidly,generating pores in-situ at the original position of S particles.Electrochemical analysis shows that the pores inside electrodes are able to shorten lithium ion diffusion paths,reduce normal expansion rate and decrease formation of cracks in the Si electrode(2 mg_(Si)/cm^(2)),demonstrating a reversible capacity of 951 mAh/g at 0.5 A/g after 100 cycles(with a capacity retention of 99.5%)and a capacity of-826 mAh/g at 2 A/g.

Experimental investigation of electrode cycle performance and electrochemical kinetic performance under stress loading

Lithium-ion batteries suffer from mechano–electrochemical coupling problems that directly determine the battery life. In this paper, we investigate the electrode electrochemical performance under stress conditions, where seven tensile/compressive stresses are designed and loaded on electrodes, thereby decoupling mechanics and electrochemistry through incremental stress loads. Four types of multi-group electrochemical tests under tensile/compressive stress loading and normal package loading are performed to quantitatively characterize the effects of tensile stress and compressive stress on cycle performance and the kinetic performance of a silicon composite electrode. Experiments show that a tensile stress improves the electrochemical performance of a silicon composite electrode, exhibiting increased specific capacity and capacity retention rate, reduced energy dissipation rate and impedances, enhanced reactivity, accelerated ion/electron migration and diffusion, and reduced polarization. Contrarily, a compressive stress has the opposite effect, inhibiting the electrochemical performance. The stress effect is nonlinear, and a more obvious suppression via compressive stress is observed than an enhancement via tensile stress. For example, a tensile stress of 675 k Pa increases diffusion coefficient by 32.5%, while a compressive stress reduces it by 35%. Based on the experimental results, the stress regulation mechanism is analyzed. Tensile stress loads increase the pores of the electrode material microstructure, providing more deformation spaces and ion/electron transport channels. This relieves contact compressive stress, strengthens diffusion/reaction, and reduces the degree of damage and energy dissipation. Thus, the essence of stress enhancement is that it improves and optimizes diffusion, reaction and stress in the microstructure of electrode material as well as their interactions via physical morphology.

<i>In Situ</i>Imposing Bias ATR-FTIR Observation at Hydrogen Terminated Si(111) Electrode Surface-Modified with Adsorbed Monolayer

Since hydrogen-terminated Si surface has hydrophobicity, it is expected that adsorbed monomolecular film of surfactant will be formed on the Si surface in aqueous solution containing the surfactant. Such an adsorbed monolayer film is very effective for the development of a functional electrode. In this study, we have investigated the state of adsorption about an aerosol OT as the monolayer on the electrode surface and its orientation with hydrogen-terminated Si(111) surface by in situ ATR-FTIR spectroscopy. At this time, in situ observation performed while imposing bias to the electrode. The results suggested that the aerosol OT were desorbed by the oxidation of back-bonds in the Si atoms on the electrode surface under the imposing noble potential, although no change was observed especially when imposing less-noble potential.

硅光子调制器行波电极研究进展

硅光子调制器是硅基光学链路中重要的电光转换元件,而行波电极作为硅光调制器承载微波信号的关键部分,其性能是决定调制器的调制效率和传输损耗的关键因素。目前,行波电极的设计主要分为共面波导结构(Coplanar Waveguide,CPW)和共面带状线结构(Coplanar Stripline,CPS),共面带状线相对于共面波导具有更大的设计匹配范围,但信号屏蔽能力会低于CPW的双接地系统,导致高阶模式激发和多模干涉等问题出现。为优化调制器性能,许多学者提出手指形延伸电极,T型延伸电极,分段电极等形状来优化电极结构,实现阻抗匹配的同时,增强电光相互作用并降低传输损耗。本文综述了国内外学者对于行波电极的研究成果,并对行波电极的发展趋势进行了分析与展望。

A Diamond Electrochemical Cleaning Technique for Organic Contaminants on Silicon Wafer Surfaces

Peroxodiphosphate anion （a powerful oxidant） can be formed in a special water-based cleaning agent through an electrochemical reaction on boron-doped diamond electrodes. This electrochemical reaction was applied during the oxidation,decomposition, and removal of organic contaminations on a silicon wafer surface, and it was used as the first step in the diamond electrochemical cleaning technique （DECT）. The cleaning effects of DECT were compared with the RCA cleaning technique, including the silicon surface chemical composition that was observed with X-ray photoelectron spectroscopy and the morphology observed with atomic force microscopy. The measurement results show that the silicon surface cleaned by DECT has slightly less organic residue and lower micro-roughness,so the new technique is more effective than the RCA cleaning technique.

Diagnosing health in composite battery electrodes with explainable deep learning and partial charging data

Lithium-ion batteries with composite anodes of graphite and silicon are increasingly being used. However, their degradation pathways are complicated due to the blended nature of the electrodes, with graphite and silicon degrading at different rates. Here, we develop a deep learning health diagnostic framework to rapidly quantify and separate the different degradation rates of graphite and silicon in composite anodes using partial charging data. The convolutional neural network (CNN), trained with synthetic data, uses experimental partial charging data to diagnose electrode-level health of tested batteries, with errors of less than 3.1% (corresponding to the loss of active material reaching ∼75%). Sensitivity analysis of the capacity-voltage curve under different degradation modes is performed to provide a physically informed voltage window for diagnostics with partial charging data. By using the gradient-weighted class activation mapping approach, we provide explainable insights into how these CNNs work;highlighting regions of the voltage-curve to which they are most sensitive. Robustness is validated by introducing noise to the data, with no significant negative impact on the diagnostic accuracy for noise levels below 10 mV, thus highlighting the potential for deep learning approaches in the diagnostics of lithium-ion battery performance under real-world conditions. The framework presented here can be generalised to other cell formats and chemistries, providing robust and explainable battery diagnostics for both conventional single material electrodes, but also the more challenging composite electrodes.

外部载荷对硅电极锂电池循环性能的影响

硅具有高比容量和低电压平台等优点,被认为是最有前途的锂离子电池负极材料之一。然而,硅电极在锂化/脱锂过程中巨大的体积膨胀以及伴随的材料破裂和粉化,限制了其倍率性能和循环性能。现有研究表明,在循环过程中对硅电极施加外部载荷能有效提高电池的循环性能。本研究提出了一种宏观调控方法,即通过施加外部机械载荷以提高硅电极锂离子电池的容量保持率。采用设计定制的原位充放电加压实验设备,以CR2032纽扣电池为对象开展实验,通过充放电循环测试验证了该方法的有效性。实验结果显示,在CR2032电池表面施加0.2 MPa大小的轴向外部载荷,可以有效抑制硅电极在充放电过程中的膨胀,并调节电池内部状态。经过50个充放电循环后,电池容量保持率将从无外部载荷时的59%提升至70%。同时,由于硅电极活性物质颗粒在锂化和脱锂过程中存在不同的应力状态,提出了一种新的调控方法,即在循环过程中在电极材料的锂化阶段施加0.1 MPa大小的外部载荷,并在脱锂阶段施加0.2 MPa的载荷。实验结果证明,该方法可以进一步提高硅电极锂离子电池的循环性能。此外,电极表面的扫描电子显微镜成像结果也支持了这一结论。本研究采用的外部机械载荷施加方法,为从宏观角度提高硅负极锂离子电池性能提供重要的借鉴。

曲面硅电极五轴精密磨削工艺研究

近两年出现了新型刻蚀技术,将半导体刻蚀用硅电极设计成曲面结构。而曲面硅电极的精度及粗糙度要求非常高,其生产都是在国外进行,具体工艺未知。研究出一套曲面硅电极高效、精密磨削方法。通过分析曲面硅电极零件,提出采用五轴磨削技术进行加工的工艺方案,使用五轴编程软件进行编程,采用具备机内自动化技术和数字仿真技术的五轴磨削中心,对曲面硅电极的磨削加工策略进行验证。结果表明:此项加工技术可提高加工效率和产品良率,并减少后续的研磨抛光时间,降低了生产成本。

锂离子电池负极材料技术进展

锂离子电池技术经过二十余年在3C领域的广泛应用已发展至新能源汽车和储能电站领域,成为近年来推动相关领域爆发式成长的核心科技。以石油焦为原料的碳材料为起点,锂离子电池负极材料经过了三十余年的商业化发展,获得了空前进步。本文梳理了近三十年锂离子电池负极材料的技术变迁,为相关领域的研究者提供负极材料研究发展系统的介绍。

硅基负极材料及硅氧负极材料的研究进展

为了解决能源危机,储能技术需要不断发展。电池应用市场不断扩大,对能量和功率密度要求越来越高,选用高比容量负极材料是实现该目标的重要策略。硅具有3579 mAh/g的容量,有望取代石墨电极,但受到大体积膨胀和不稳定的固体电解质界面的限制。氧化亚硅负极具有2600 mAh/g的高理论比容量和较好的循环稳定性,是有前景的锂离子电池负极材料。然而,硅基负极材料和硅氧负极材料在循环过程中的体积效应和固有电导率较差,限制了实际应用。目前,硅基负极的改性化方法主要包括纳米晶化、硅-碳复合材料、优化电解液和添加剂等方法。本文将对硅基负极材料及硅氧负极材料的研究成果进行总结和展望。

DEPs/木质素复合黏结剂的制备及性能研究

目的低共熔聚合物(DEPs)具有绿色环保、可设计性及生物相容性等特性,通过共混木质素(Lignin)合成制备具有良好的力学性能、热学性能和电化学性能的聚合物复合黏结剂,并探索其在新能源电池电极涂层领域的应用。方法以合成得到的可聚合低共熔溶剂(PDES)单体为基底,共混不同质量分数的木质素得到不同比例的PDES单体/木质素复合材料,通过热引发聚合制备得到DEPs/木质素复合黏结剂,并对复合黏结剂进行结构、力学性能、热学性能、表面形貌的分析,并在锂离子电池应用中探究电化学性能。结果通过实验得出,当选用一水合甜菜碱(betaine)-丙烯酸(AA)型PDES单体,木质素质量分数为6%时,制备的DEPs/木质素复合黏结剂综合各项性能最优,应用在硅(Si)电极中能够较好地控制体积变化问题,获得良好的电化学性能。结论制备获得了DEPs/木质素复合黏结剂,该黏结剂绿色环保、成本低、合成工艺简单、各项性能优异,可应用于新能源锂电池领域以及扩大木质素高价值化利用途径。

软包动力电池硅氧负极材料的合成与应用研究

本文主要讨论了软包动力电池中锂合氧化硅负极材料的合成和应用。本文首先探讨了动力电池的重要性以及材料科学在电池技术中的关键角色,随后详述了电池工作原理,负极材料的作用,以及锂合氧化硅作为负极材料的理论背景。在合成方面,详细描述前驱体的选择和处理等其他影响因素,最后讨论了锂合氧化硅负极材料在软包动力电池中的应用,尤其是其对电池性能和稳定性的影响。尽管锂合氧化硅复合负极材料面临诸多挑战,但其也为电池性能的提高带来新的可能,值得进一步的研究和开发。

“自愈合”硅基电极材料的制备研究

合成了具有“自愈合”功能的高分子材料,并将其作为黏合剂应用于光伏行业回收切割高纯硅粉中,制备得到有效缓解硅基材料膨胀粉化问题的低成本高性能锂离子电池电极,对材料进行模拟电池测试,首次比容量达到了609.72 mAh/g,循环100次后容量下降为508.85 mAh/g。为未来锂离子电池用硅材料的规模化生产和商业化应用提供了一条崭新的技术路线。

锂离子电池硅基负极材料的制备及其性能表征

使用Si粉、SiO_(2)粉、丙烯作为主要原料在高温条件下反应制备得到硅基内核,用碳酸钠-氢氧化钠、三聚磷酸硅对硅基内核进行包覆,制备了一种高性能锂离子电池硅基负极材料,对样品的粒度、XRD、SEM等进行了表征,结果表明其具有良好的导电性。采用该负极材料制备了扣式电池并测试其循环性能,结果表明该材料制备的电池性能优异。

气相沉积法制备多孔硅炭负极材料及其性能研究

环境保护和可再生能源利用是世界各国共同的选择,但可再生能源容易受外部因素影响而不能稳定供应,人们需要合适的能源装置进行储存才能形成稳定供应。锂离子电池因其优秀的电化学性能成为了现今最主要的新能源电池,但目前商业化锂离子电池的负极材料主要以人造石墨和天然石墨等石墨类材料为主,石墨类型负极材料的理论比容量只有372 mAh/g,不能满足各国对高能量密度的发展规划和要求,急需研制更高比容量的新一代负极材料。使用气相沉积法制备出了最新一代高容量多孔硅炭负极材料,并对其物理性能和电化学性能进行了研究,发现其比容量可高达2000 mAh/g以上,硅材料的体积膨胀问题也得到了极大的改善。

Review on Metallization Approaches for High-Efficiency Silicon Heterojunction Solar Cells

Crystalline silicon(c-Si)heterojunction(HJT)solar cells are one of the promising technologies for next-generation industrial high-efficiency silicon solar cells,and many efforts in transferring this technology to high-volume manufacturing in the photovoltaic(PV)industry are currently ongoing.Metallization is of vital importance to the PV performance and long-term reliability of HJT solar cells.In this review,we summarize the development status of metallization approaches for highefficiency HJT solar cells.For conventional screen printing technology,to avoid the degradation of the passivation properties of the amorphous silicon layer,a low-temperature-cured(<250℃)paste and process are needed.This process,in turn,leads to high line/contact resistances and high paste costs.To improve the conductivity of electrodes and reduce the metallization cost,multi-busbar,fine-line printing,and low-temperature-cured silver-coated copper pastes have been developed.In addition,several potential metallization technologies for HJT solar cells,such as the Smart Wire Contacting Technology,pattern transfer printing,inkjet/FlexTrailprinting,and copper electroplating,are discussed in detail.B ased on the summary,the potential and challenges of these metallization technologies for HJT solar cells are analyzed.