LiSi／FeS2热电池失效机理分析

热电池的失效主要是由于生产环境控制不严导致电池材料吸潮后水份与电极材料发生反应的结果。本文简要分析了热电池失效的三种主要因素。     

LiB/NiCl_2体系热电池抗力学性能的研究

本文研究了Li B/Ni Cl2体系热电池的抗振动、离心旋转力学性能。结果表明,该体系热电池可在均方根29g随机振动和径向3286.5m/s2离心旋转的苛刻力学条件下正常放电。Li B/Ni Cl2体系热电池优异的抗力学性能为其今后的工程化应用奠定了坚实的基础。     

热电池薄膜电极制备及其电化学性能

热电池因具有高能量密度、储存寿命长等优点被应用于特殊领域。随着电子设备的小型化,热电池也向着小型化、薄膜化发展。采用涂覆法将正极材料FeS2制备成薄膜材料,并与传统压制成型材料对比。涂覆法制备的材料厚度在120 μm,电流密度为100 mA?cm-2,1 A?cm-2时,放电容量分别高达821 mAh?g-1,528 mAh?g-1,相比传统方法,放电容量增加20%~30%,电池内阻仅有81 mΩ。装配成电池组的电性能更加明显,放电容量较传统提高了153%,同时在重量和体积上都具有明显的优势。     

热电池用加热材料的性能研究

通过测试不同配比加热材料的性能，以及对这些性能参数的分析和比较，得出影响加热材料性能的一些因数，为热电池的加热系统设计提供参考。     

锂氧电池复合电解质电化学性能研究

将LiPF_6溶入EC/EMC/DMC作为锂氧电池电解质主体,并分别加入[Emim]BF_4和[DEME]TFSI离子液体制成复合电解质材料,组装成锂氧电池。通过循环伏安、交流阻抗、恒流充放电等方式研究复合电解质的电化学性能。结果表明,LiPF_6溶入EC/EMC/DMC-[Emim]BF_4体系复合电解质表现出较优的电化学性能,在0.025×10~(–3)A·cm~(–2)电流密度下电池首次放电比容量为2 672×10~(–3)Ah·g~(–1),能量密度达6.468×10~(–3) Wh·cm~(–2)。     

加速量热仪在锂离子电池热安全性能方面的研究

加速量热仪(ARC)是应用于锂离子电池安全性能研究的新型热分析仪器,可提供绝热环境下化学反应的时间、温度和压力等数据.该文详细介绍了加速量热仪工作的基本原理.重点研究了电极材料与电解液反应热特性、锂离子电池的热稳定性、比热容测试、充放电过程中锂离子电池的热行为.对加速量热仪在锂离子电池热安全性能的研究方向进行了展望.     

溶剂热处理法制备的钙钛矿CH3NH3PbI3薄膜的微观形貌与电池性能的研究

近年来研究表明,通过增大晶粒尺寸和减少晶界数量可以有效减小钙钛矿太阳能电池的漏电流和增大并联电阻,极大地增加其能量转化效率。溶剂热处理工艺是一种利用溶解再结晶的原理增大薄膜晶粒的实用工艺,可用于制备大晶粒高质量的多晶薄膜。本文制备了不同溶剂热处理时长的旋涂制备的钙钛矿CH₃NH₃PbI₃薄膜,利用SEM和XRD分析了其形貌和晶体结构的变化,探索了薄膜晶粒形貌与电池性能的对应关系,应用优化后的溶剂热处理工艺成功制备出大晶粒、高性能的钙钛矿薄膜。实验表明,溶剂热处理法制备的钙钛矿CH₃NH₃PbI₃薄膜平均晶粒尺寸接近3μm,较普通热处理方法制备的薄膜晶粒尺寸(约300 nm)有显著增大。     

Toward High‐Performance Hybrid Zn‐Based Batteries via Deeply Understanding Their Mechanism and Using Electrolyte Additive

Aqueous hybrid Zn‐based batteries (ZIBs), as a highly promising alternative to lithium‐ion batteries for grid application, have made considerable progress recently. However, few studies have been reported that investigate their working mechanism in detail. Here, the operando synchrotron X‐ray diffraction is employed to thoroughly investigate the operational mechanism of a hybrid LiFePO₄(LFP)/Zn battery, which indicates only Li⁺ extraction/insertion from/into cathode during cycling. Based on this system, a cheap electrolyte additive, sodium dodecyl benzene sulfonate, is proposed to effectively enhance its electrochemical properties. The influence of the additive on the Zn anode and LFP cathode is comprehensively studied, respectively. The results show that the additive modifies the intrinsic deposit pattern of Zn²⁺ ions, rendering Zn plating/stripping highly reversible in an aqueous medium. On the other hand, the wettability of the LFP electrode is visibly a meliorated by introducing the surfactant additive, accelerating the Li‐ion diffusion at the LFP electrode/electrolyte interface, as indicated by the overpotential measurements. Benefiting from these effects, the Zn/LFP batteries deliver high rate capability and cycling stability in both coin cells and pouch cells.     

Rational Designs for Lithium-Sulfur Batteries with Low Electrolyte/Sulfur Ratio

Lithium-sulfur batteries (LSBs) are considered a promising next-generation energy storage device owing to their high theoretical energy density. However, their overall performance is limited by several critical issues such as lithium polysulfide (PS) shuttles, low sulfur utilization, and unstable Li metal anodes. Despite recent huge progress, the electrolyte/sulfur ratio (E/S) used is usually very high (≥20 µL mg⁻¹), which greatly reduces the practical energy density of devices. To push forward LSBs from the lab to the industry, considerable attention is devoted to reducing E/S while ensuring the electrochemical performance. To date, however, few reviews have comprehensively elucidated the possible strategies to achieve that purpose. In this review, recent advances in low E/S cathodes and anodes based on the issues resulting from low E/S and the corresponding solutions are summarized. These will be beneficial for a systematic understanding of the rational design ideas and research trends of low E/S LSBs. In particular, three strategies are proposed for cathodes: preventing PS formation/aggregation to avoid inadequate dissolution, designing multifunctional macroporous networks to address incomplete infiltration, and utilizing an imprison strategy to relieve the adsorption dependence on specific surface area. Finally, the challenges and future prospects for low E/S LSBs are discussed.     

Electrolyte‐Regulated Solid‐Electrolyte Interphase Enables Long Cycle Life Performance in Organic Cathodes for Potassium‐Ion Batteries

Organic cathode materials as economical and environment‐friendly alternatives to inorganic cathode materials have attracted comprehensive attention in potassium‐ion batteries (KIBs). Nonetheless, active material dissolution and mismatched electrolytes result in insufficient cycle life that definitely hinders their practical applications. Here, a significantly improved cycle life of 1000 cycles (80% capacity retention) on a practically insoluble organic cathode material, anthraquinone‐1,5‐disulfonic acid sodium salt, is realized, in KIBs through a solid‐electrolyte interphase (SEI) regulation strategy by ether‐based electrolytes. Such an excellent performance is attributed to the robust SEI film and fast reaction kinetics. More importantly, the ether‐electrolyte‐derived SEI film has a protective inorganic‐rich inner layer arising from the prior decomposition of potassium salts to solvents, as revealed by X‐ray photoelectron spectroscopy analysis and computational studies on molecular orbital energy levels. The findings shed light on the critical roles of electrolytes and the corresponding SEI films in enhancing performance of organic cathodes in KIBs.     

高比能水体系锂电池研究

实现水溶液锂电池的关键技术是如何保护金属锂电极不与水反应。提出了一种保护金属锂电极,其不仅在有机电解液体系稳定而且在水溶液中也可稳定工作,这种锂电极可以用于水体系锂电池。该研究制备了双层锂离子电解质保护的金属锂电极,其外层采用的LAGP（Li1＋x＋yAlxGe2-x SiyP3-yO12）玻璃陶瓷电解质相对于包括水溶液等电解液是稳定的,该玻璃陶瓷电解质的电导率达到0.57 mS cm^-1。通过交流阻抗评估发现不同电解质间的界面阻抗是水体系锂电池内阻的主要来源。最终采用双层保护金属锂电极制备的水体系锂空气电池和锂水电池可以稳定工作。     

Inorganic Filler Enhanced Formation of Stable Inorganic-Rich Solid Electrolyte Interphase for High Performance Lithium Metal Batteries

Lithium metal (LM) is a promising anode material for next generation lithium ion based electrochemical energy storage devices. Critical issues of unstable solid electrolyte interphases (SEIs) and dendrite growth however still impede its practical applications. Herein, a composite gel polymer electrolyte (GPE), formed through in situ polymerization of pentaerythritol tetraacrylate with fumed silica fillers, is developed to achieve high performance lithium metal batteries (LMBs). As evidenced theoretically and experimentally, the presence of SiO₂ not only accelerates Li⁺ transport but also regulates Li⁺ solvation sheath structures, thus facilitating fast kinetics and formation of stable LiF-rich interphase and achieving uniform Li depositions to suppress Li dendrite growth. The composite GPE-based Li||Cu half-cells and Li||Li symmetrical cells display high Coulombic efficiency (CE) of 90.3% after 450 cycles and maintain stability over 960 h at 3 mA cm⁻² and 3 mAh cm⁻², respectively. In addition, Li||LiFePO₄ full-cells with a LM anode of limited Li supply of 4 mAh cm⁻² achieve capacity retention of 68.5% after 700 cycles at 0.5 C (1 C = 170 mA g⁻¹). Especially, when further applied in anode-free LMBs, the carbon cloth||LiFePO₄ full-cell exhibits excellent cycling stability with an average CE of 99.94% and capacity retention of 90.3% at the 160th cycle at 0.5 C.     

AGM隔膜对VRLA电池性能的影响

介绍了超细玻璃纤维隔膜（AGM）的基本性能以及不同厂家AGM隔膜在相同的极板和装配压力等情况下对所装配电池初期容量、电解液分层情况、密封反应效率、电池循环寿命等的影响。     

LED热性能测试技术的机理及研究进展

热性能参数是衡量LED整体性能优劣的重要指标,对LED的结温、热阻等参数进行精确测试是有效热管理的前提,也是完善LED性能评价标准的必要条件。在充分调研LED热性能测试方法的基础上,对国内外现有的热测试技术进行了介绍,讨论了各方法的测试机理,分析比较了各自的优缺点和适用范围,并简要介绍了相关的测试设备。     

Utilizing Magnetic-Field Modulation to Efficiently Improve the Performance of LiCoO2||Graphite Pouch Full Batteries

The present lithium-ion battery technology competition almost focuses on finding new materials, while less effort is invested in electrode engineering improvement with low-cost. This study proposes a simple method of modulating the preferred orientation of crystal phases in LiCoO₂ electrode using a ≈500 mT magnetic-field, cheaply and efficiently improving the performance of LiCoO₂||graphite pouch full batteries, including cycling stability, rate performance, and thermal safety performance. Under 3.0 C and 45 °C strict test conditions, LiCoO₂-M_⊥||graphite battery even outputs the capacity retention rate of 42.8% after 1000 cycles, while that of pure-LiCoO₂ battery is only 4.4%. Especially, the thermal runaway temperature of the battery needling experiment decreases by considerable 7.7 °C after magnetic-field modulation. Comprehensive characterizations reveal that vertical magnetic field causes spin alignment of LiCoO₂ crystals along the (003) direction. This arrangement effectively improves the Li⁺ diffusion dynamic and the interface compatibility of the electrode, suppressing the electrode polarization. During the cycling processes, the preferred orientation of LiCoO₂ particles forms an enhanced conductive network due to the formation of cross-linked “Li⁺ poor regions” on the surface, ultimately achieving significant performance improvement. This work can provide a potential low-cost strategy for the production of commercial lithium-ion batteries.     

射频功率模块的热性能分析

随着高密度电子组装技术的不断发展,电子设备的体积越来越小,而功率却越来越大。热功耗的显著增加将对半导体芯片的正常工作产生很大的影响。对装有功率放大器芯片的射频模块热性能进行了分析,提出了有效热控制的解决方法,为射频功率模块的可靠、稳定工作提供了保障。     

Enhanced Interfacial Stability of Hybrid‐Electrolyte Lithium‐Sulfur Batteries with a Layer of Multifunctional Polymer with Intrinsic Nanoporosity

The use of lithium‐ion conductive solid electrolytes offers a promising approach to address the polysulfide shuttle and the lithium‐dendrite problems in lithium‐sulfur (Li‐S) batteries. One critical issue with the development of solid‐electrolyte Li‐S batteries is the electrode–electrolyte interfaces. Herein, a strategic approach is presented by employing a thin layer of a polymer with intrinsic nanoporosity (PIN) on a Li⁺‐ion conductive solid electrolyte, which significantly enhances the ionic interfaces between the electrodes and the solid electrolyte. Among the various types of Li⁺‐ion solid electrolytes, NASICON‐type Li_1+xAl_xTi_2‐x(PO₄)₃ (LATP) offers advantages in terms of Li⁺‐ion conductivity, stability in ambient environment, and practical viability. However, LATP is susceptible to reaction with both the Li‐metal anode and polysulfides in Li‐S batteries due to the presence of easily reducible Ti⁴⁺ ions in it. The coating with a thin layer of PIN presented in this study overcomes the above issues. At the negative‐electrode side, the PIN layer prevents the direct contact of Li‐metal with the LATP solid electrolyte, circumventing the reduction of LATP by Li metal. At the positive electrode side, the PIN layer prevents the migration of polysulfides to the surface of LATP, preventing the reduction of LATP by polysulfides.