摘要：The olivine-type lithium iron phosphate(LiFePO_(4))cathode material is promising and widely used as a high-performance lithium-ion battery cathode material in commercial batteries due to its low cost,environmental friendliness,and high *** present,LiFePO_(4)/C sec-ondary batteries are widely used for electronic products,automotive power batteries,and other occasion-related applications with good thermal stability,stable cycle performance,and low room-temperature self-discharge ***,LiFePO_(4)-based battery applications are seriously limited when they are operated in a cold *** outcome is due to a considerable decrease in Li+transport capabilities within the elec-trode,particularly leading to a dramatic decrease in the electrochemical capacity and power performance of the ***,the design of low-temperature electrolytes is important for the further commercial application of LiFePO_(4) *** paper reviews the key factors for the poor low-temperature performance of LiFePO_(4)-based batteries and the research progress of low-temperature ***-cial attention is paid to electrolyte components,including lithium salts,cosolvents,additives,and the development of new *** factors affecting the anode are also ***,according to the current research progress,some viewpoints are summarized to provide suitable modification methods and research suggestions for improving the practicability of LiFePO_(4)/C commercial batteries at low temperat-ures in the future.

摘要：基于密度泛函理论(DFT)的第一原理方法计算了四方相和立方相中2种不同的Li_(7)La_(3)Zr_(2)O_(12)(LLZO)固体电解质材料的能带结构,晶格参数,态密度和成键特性。基于理论计算结果,通过电子结构特性解释了四面体相的离子电导率低于立方相的离子电导率的原因。基于LLZO的第一性原理计算,设计了2种晶体结构的LLZO材料,并通过高温固相法制备并分析了不同烧结时间的LLZO颗粒的性能。探索了合成工艺参数对Li_(7)La_(3)Zr_(2)O_(12)性能的影响。立方晶Li_(7)La_(3)Zr_(2)O_(12)(C-LLZO)的平均晶格大小为a=b=c=1.302 246 nm,而四方Li_(7)La_(3)Zr_(2)O_(12)(T-LLZO)的平均晶格大小为a=b=1.313 064 nm,c=1.266 024 nm。在1000℃下烧结12 h的C-LLZO为纯立方相,在室温(25℃)下最大离子电导率为9.8×10^(-5) S·cm^(-1)。T-LLZO在室温(25℃)下的离子电导率为5.96×10^(-8) S·cm^(-1),在800℃下烧结6 h具有纯的四方相结构,与计算结果基本吻合。

摘要：龙眼是起源于中国热带地区的一种珍贵水果树木,龙眼木密实硬重、纹理细腻、材质坚韧、材色名贵,是优良的雕刻和家具用材。为进一步提高其利用价值,通过扫描电镜技术研究了龙眼木的超微观构造特征。以龙眼木超微观特征为素材,采用分形图案设计等方法,创作木材美学图案。然后根据木材美学图案,开展以龙眼木构造特征为美学元素的艺术作品设计,从而发掘龙眼木的美学利用价值。扫描电镜分析结果表明,龙眼木生长轮不明显,为散孔材,单管孔、径列复管孔或管孔团。导管为单穿孔,管间纹孔式为互列,纹孔为椭圆形或多角形,纹孔内口外延,多出现几个外延纹孔口相连合生的状态,在导管内壁形成长条形凹槽,且离穿孔越近,合生纹孔口的凹槽越长,以至于在靠近穿孔的区域演变为类似密集螺纹加厚的构造。龙眼木的木射线较细,肉眼下不明显,多为单列射线,偶有多列,高2~14个细胞。射线细胞全为横卧细胞,截面为方形或椭圆形,胞腔内多含有珍珠般晶莹泛亮的淀粉颗粒。龙眼木的轴向薄壁组织为环管和傍管带状,带宽4~6个细胞,细胞腔内多含有菱形晶体。龙眼木中有些超微观构造特征,如导管内壁上特殊的合生纹孔口结构和木射线薄壁细胞腔内珍珠般淀粉颗粒,除了具有树木生理和木材鉴别方面的意义,还具有很好的审美价值,可以作为美学元素,应用于装饰挂画和手包等生活用品的美饰设计。