LWD仪器临界电压数据读取分析与解决

锂电池是LWD仪器正常工作的动力来源,是仪器的心脏。仪器出井后,需要在井口读取数据,当锂电池的电量接近耗尽时,会导致数据读取失败的问题。该问题处理不当,会造成长期占用井口,影响钻井时效,严重时还可能会因短路造成昂贵的LWD仪器损坏。锂电池的临界电压问题暴露了该仪器的设计缺陷,在此通过技术方法充分利用INSITE系统本身提供的功能,绕过其设计缺陷将问题解决。     

A matryoshka-like CuS@void@Co3O4 double microcube-locked sulfur as cathode for high-performance lithium-sulfur batteries

Lithium-sulfur battery cathodes still remain a challenge on capacity decay due to the shuttle effect even though a series of strategies have been tried. Here we report a novel matryoshka-like CuS@void@Co₃O₄ architecture of double micro-cubes (μ-cubes) that locks sulfur between the CuS core and the Co₃O₄ shell. Plenty of existing spaces between the μ-cubes suffice a high loading of sulfur and volumetric accommodation. The robust, double closed cubes configuration greatly enhances the confinement of polysulfides. In parallel, the CuS core increases the electronic conductivity and contributes to additional capacity, while the Co₃O₄ shell ensures a better interface activity. A high Li⁺ ion diffusion coefficient is obtained during the sulfur and lithium sulfide transformation. The constructed battery displays an initial capacity up to 1480 mAh g⁻¹, and a Coulombic efficiency (CE) exceeding 99%. A capacity retention higher than 500 mAh g⁻¹ with a CE larger than 99.8% after cycling 400 times at 0.2 C are achieved. In addition, under a temperature of −5 °C, a high capacity of 700 mAh g⁻¹ at 0.2 C after 200 cycles is achieved, indicating a good low-temperature tolerance.     

电化学反应器隔膜材料的分子设计与介尺度策略

电化学反应器中隔膜材料是将正极和负极在电子通路上隔开但在离子传输通路上保持畅通的特殊材料。作为电化学反应器三个关键材料之一，隔膜材料还需耐强酸/强碱和高电压等环境。围绕电化学反应器中隔膜材料，从分子设计的角度针对材料电化学性能与化学稳定性的调控、电化学装置的介观传质性能的促进和改善等研究思路与进展进行了综述，为相关研究提供性能导向的分子设计参考。     

铝空气电池用6061和7075铝合金阳极电化学性能

研究了工业6061铝合金（6061）、航空7075铝合金（7075）和纯铝作为铝空气电池阳极材料的电化学性能，分析其作为阳极的可行性及适用环境。进行了阻抗、极化曲线和恒电流放电实验并进行了表面表征，计算了在40～120mA/cm²电流密度下连续恒流放电的阳极能量密度。用电子探针显微镜（EPMA）对电极表面形貌进行了研究，用波谱分析仪（WDS）进行表面分析。研究结果表明，合金元素在电池放电过程中会改变阳极的表面特性。6061中合金元素含量对电池阳极材料的性能产生了积极影响，使得合金的表面放电面积变大，放电均匀，更适合作为铝空气电池阳极材料。     

石墨烯负载纳米二硫化钴的制备及其在锂离子电池方面的应用研究

采用二次水热法将纳米二硫化钴负载于石墨烯上,并通过结构表征和电化学性能测试,探讨了纳米二硫化钴/石墨烯材料作为锂离子电池负极的性能。电容量测试结果表明：在电流密度为100 mA/g条件下,二硫化钴/石墨烯复合材料的首周充放电容量分别为1 610 mA·h/g和774 mA·h/g,测算出的库伦效率为48.1%;循环性能测试结果表明：经过50次循环测算后的复合材料的放电比容量为302 mA·h/g,容量保持率为33.4%;倍率性能测试结果表明：当电流密度回复到100 mA/g时,复合材料的比容量恢复至550 mA·h/g。实验制备的纳米二硫化钴/石墨烯复合材料在锂电池负极的应用上表现出了优异的循环性能和倍率性能。     

镍钴锰酸锂正极材料 LiNi1/3Mn1/3Co1/3O2的制备方法和研究进展

LiNi1/3Co1/3Mn1/3O2很好的构成了LiNiO2/LiCoO2/LiMnO2三类材料的固溶体系，兼容了三种材料的优点且弥补了上述材料作为正极材料的不足，是备受欢迎的锂电池正极材料。详细叙述了该正极材料的结构特征和电化学反应特征及近几年国内外对111型镍钴锰酸锂正极材料的研究进展，介绍了固相法，共沉淀法和溶胶凝胶法等方法的原理和特点，并阐述了掺杂和包覆改性对正极材料电化学性能的影响。     

Balancing the specific surface area and mass diffusion property of electrospun carbon fibers to enhance the cell performance of vanadium redox flow battery

Electrospun carbon fibers are featured with abundant electroactive sites but large mass transport resistances as the electrodes for vanadium redox flow battery. To lower mass transport resistances while maintaining large specific areas, electrospun carbon fibers with different structural properties, including pore size and pore distribution, are prepared by varying precursor concentrations. Increasing the polyacrylonitrile concentration from 9 wt% to 18 wt% results in carbonized fibers with an average fiber diameter ranging from 0.28 μm to 1.82 μm. The median pore diameter, in the meantime, almost linearly increases from 1.32 μm to 9.05 μm while maintaining the porosity of higher than 82%. The subsequent electroactivity evaluation and full battery testing demonstrate that the mass transport of vanadium ions through the electrode with larger fiber diameters are significantly improved but not scarifying the electrochemical activity. It is shown that the flow battery with these electrodes obtains an energy efficiency of 79% and electrolyte utilization of 74% at 300 mA cm⁻². Hence, all these results eliminate the concern of mass transport when applying electrospun carbon fibers as the electrodes for redox flow batteries and guide the future development of electrospun carbon fibers.     

采用泡沫铜电极的热再生氨电池性能数值模拟

以采用泡沫铜电极的热再生氨电池（thermally regenerative ammonia-based battery，TRAB）为研究对象，建立了多孔介质内物质传输与电化学反应耦合的稳态模型，计算获得了电池性能及多孔电极内物质传输特性，并研究了电解质浓度和电极孔隙率对电池性能的影响。研究结果表明，从主流区界面到多孔电极内部，阳极氨和阴极铜离子浓度逐渐降低，存在一定的浓度梯度，而且随着反应电流的增大，浓度梯度明显增大。在一定的范围内分别增大阳极氨浓度和阴极铜离子浓度，从主流区向多孔电极内物质传输增强，电池性能均能不断提升；随着硫酸铵浓度的增大，电解质电导率增大，电池性能逐渐提升，但增幅逐渐减小。此外，多孔电极孔隙率也会影响电池性能，本研究中TRAB在电极孔隙率为0.6时获得最高的最大功率(15.3 mW)。     

Highly stable graphene oxide composite proton exchange membrane for electro-chemical energy application

Proton exchange membrane is a basic element for any redox flow battery. Nafion is the only commercial available proton exchange membrane used in different electro-chemical energy systems. High cost restrict it's used for energy generation devices. In present work, we synthesised styrene divinylbenzene based composite proton exchange membranes (PEMs) with varying sulfonated graphene oxide (sGO) content for redox flow battery (RFB). Synthesized copolymer PEMs were analyzed in terms of their chemical structure with the help of FT-IR spectroscopy to confirm desired functional groups at appropriate position. Electrochemical characterization was performed in terms proton-exchange capacity, protonic conductivity and water uptake. Membrane shows adequate proton exchange capacity with good proton conductivity. Vanadium ion permeability was also tested for the prepared membrane to assess capability for vanadium redox flow battery (VRFB) in contrast with commercially available Nafion 117 PEM. Higher VO⁺² ion cross-over resistance was found for CEM-4 with 7.17 × 10⁻⁷ cm² min⁻¹ permeability, which is about half of the CEM-1. Further CEM-4 was also evaluated for charging-discharging phenomenon for single cell VRFB. The values of columbic, voltage and energy efficiency for VRFB confirms prepared membrane as a good candidate for redox flow battery. Composite PEM also shows better mechanical and thermal stability. Results indicates that synthesized composite membrane can be used in vanadium redox flow battery.     

锂离子电池硅基负极黏结剂研究进展

硅在自然界中储量丰富,其理论比容量高达4 200 mA∙h/g,已成为高能量密度锂离子电池负极材料的研究热点。但是Si作为负极材料也存在许多不足,最大的问题是电池充放电过程中,硅体积膨胀（高达300%）,导致Si基负极材料粉化脱落、电池容量迅速衰减,其循环性能尚难以满足实际需求。通过研究开发硅基负极专用黏结剂材料,可以有效抑制循环过程中硅的体积变化,维持硅负极结构稳定,提升电池循环性能。本文综述了近年来硅基负极黏结剂材料的研究进展,主要从合成高分子聚合物黏结剂、天然高分子聚合物黏结剂、导电高分子聚合物黏结剂三个方面进行详细归纳总结,并介绍了本课题组在硅基负极黏结剂方面的部分研究成果,期望能为将来的硅基负极专用黏结剂的研究和应用提供一些思路。