铅基多孔材料的反重力渗流铸造工艺与平均孔径测试

针对铅基多孔材料反重力渗流铸造新工艺,研究填料粒子预热温度、熔体温度、充型压力和填料粒子粒径等工艺参数对渗流成型过程的影响规律,获得孔径可控、结构均匀的铅基多孔阳极的制备技术.同时,针对所制备多孔材料孔径大且孔形不规则问题,提出一种适用于大孔径及孔形不规则的多孔材料平均孔径测试方法.研究结果表明:采用反重力渗流铸造法制备铅基多孔材料的关键是合理选择铸造温度、充型压力和粒子预热温度这3个工艺参数,粒径对制备工艺的影响较小;当铅液的铸造温度为430～490℃,填料粒子的预热温度为240～280℃,充型压力为0.06～0.08 MPa时制备的多孔样品渗流长度长,且孔洞均匀、缺陷少,效果最好.该方法可用于大孔径孔形不规则的多孔材料平均孔径的测量.     

Three-dimensionally macroporous graphene-supported Fe3O4 composite as anode material for Li-ion batteries with long cycling life and ultrahigh rate capability

Fe3O4 is an attractive conversion reaction- based anode material with high theoretical capacity （928 mA h g^-1）. However, the poor cycling and rate per- formance hinder its applications in Li-ion batteries. In this work, we report an effective strategy to synthesize three- dimensionally macroporous graphene-supported Fe3O4 hybrid composite. Benefiting from advantage of the special structure, the hybrid composite exhibits excellent Li^＋ stor- age performance, delivering a high reversible capacity of 980 mA h g^-1at the current density of 4 A g^-1 even after 470 cycles and ultrahigh rate capability （293 mA h g^- 1 even at current density of 20 A g^-1）.     

应变诱导熔体活化处理对Zn牺牲阳极组织和性能的影响

The microstructural properties and electrochemical performance of zinc (Zn) sacrificial anodes during strain-induced melt activation (SIMA) were investigated in this study. The samples were subjected to a compressive ratio of 20%–50% at various temperatures (425–435°C) and durations (5–30 min). Short-term electrochemical tests (anode tests) based on DNV-RP-B401 and potentiodynamic polarization tests were performed in 3.5wt% NaCl solution to evaluate the electrochemical efficiency and corrosion behavior of the samples, respectively. The electrochemical test results for the optimum sample confirmed that the corrosion current density declined by 90% and the anode efficiency slightly decreased relative to that of the raw sample. Energy-dispersive X-ray spectroscopy, scanning electron microscopy, metallographic images, and microhardness profiles showed the accumulation of alloying elements on the boundary and the conversion of uniform corrosion into localized corrosion, hence the decrease of the Zn sacrificial anode’s efficiency after the SIMA process.     

镧含量对铝合金牺牲阳极海水综合电化学性能的影响

【目的】分析Al-Zn-In-Si系牺牲阳极添加不同含量配比的稀土元素镧(La)时,其电化学性能的作用规律,获得在海水环境下最佳牺牲阳极电化学性能的La添加量。【方法】通过模拟海洋环境,采用XRD分析、极化曲线、交流阻抗(EIS)和恒电流加速试验等方法,研究含La铝合金牺牲阳极的开路电位、工作电位、溶解形貌、电流效率以及极化等行为及其发生机理。【结果】La的加入改变了铝合金牺牲阳极溶质元素的存在形式,并随着含量的变化对其产生不同程度的影响;EIS谱表明含La铝合金牺牲阳极活化溶解过程体现了点蚀诱导期和发展期,极化曲线表明加入过量La后铝合金牺牲阳极的腐蚀电位变正,活化性能变差;恒电流测试实验表明加入La后铝合金牺牲阳极的电流效率有所升高。【结论】适量添加稀土元素La可有效改善铝合金牺牲阳极在海水中的电化学性能,其中La含量为0.2%的铝合金牺牲阳极电流效率最高。     

锌–空气电池抑制阳极钝化的研究进展

锌–空气电池凭借其高能量密度、电极材料资源丰富、生产成本低、储存寿命长、绿色环保无污染等优点而被广泛研究，但由于锌阳极在循环过程中存在锌枝晶生长、钝化等问题，导致锌–空气电池的实际能量密度低于理论容量密度，严重制约了其发展与应用。本文根据锌–空气电池的锌阳极工作原理和钝化机理，从电解液优化、锌阳极结构设计和表面改性等方面分析提出解决锌阳极钝化的措施，并提出了关于这些问题未来的研究方向，最后对锌–空气电池的未来发展做出展望。