Lithium (Li) metal electrodes show significantly different reversibility in the electrolytes with different salts. However, the understanding on how the salts impact on the Li loss remains unclear. Herein, using the electrolytes with different salts (e.g., lithium hexafluorophosphate (LiPF6), lithium difluoro(oxalato)borate (LiDFOB), and lithium bis(fluorosulfonyl)amide (LiFSI)) as examples, we decouple the irreversible Li loss (SEI Li+ and “dead” Li) during cycling. It is found that the accumulation of both SEI Li+ and “dead” Li may be responsible to the irreversible Li loss for the Li metal in the electrolyte with LiPF6 salt. While for the electrolytes with LiDFOB and LiFSI salts, the accumulation of “dead” Li predominates the Li loss. We also demonstrate that lithium nitrate and fluoroethylene carbonate additives could, respectively, function as the “dead” Li and SEI Li+ inhibitors. Inspired by the above understandings, we propose a universal procedure for the electrolyte design of Li metal batteries (LMBs): (i) decouple and find the main reason for the irreversible Li loss; (ii) add the corresponding electrolyte additive. With such a Li-loss-targeted strategy, the Li reversibility was significantly enhanced in the electrolytes with 1,2-dimethoxyethane, triethyl phosphate, and tetrahydrofuran solvents. Our strategy may broaden the scope of electrolyte design toward practical LMBs.

Manganese dioxide (MnO₂) is a widely used and well-studied 3-dimensional (3D) transition metal oxide, which has advantages in ultrafast optics due to large specific surface area, narrow bandgap, multiple pores, superior electron transfer capability, and a wide range of light absorption. However, few studies have considered its excellent performance in ultrafast photonics. γ-MnO₂ photonics devices were fabricated based on a special dual-core, pair-hole fiber (DCPHF) carrier and applied in ultrafast optics fields for the first time. The results show that the soliton molecule with tunable temporal separation (1.84 to 2.7 ps) and 600-MHz harmonic solitons are achieved in the experiment. The result proves that this kind of photonics device has good applications in ultrafast lasers, high-performance sensors, fiber optical communications, etc., which can help expand the prospect of combining 3D materials with novel fiber for ultrafast optics device technology.

本文在水热条件下成功合成了一例Keggin型多酸基超分子化合物1,其分子式为H3［(3-PA)4(PW12O40)］(3-PA=3-(3-吡啶)丙烯酸)，并通过单晶X射线衍射、元素分析(EA)、红外(IR)光谱、X射线粉末衍射(PXRD)、热重(TG)和固体紫外-可见(UV-Vis)漫反射对化合物1的结构进行了表征。化合物1属于三斜晶系，P-1空间群，a=1.200 33(3) nm，b=1.216 42(3) nm，c=1.424 66(4) nm，α=75.030(1)°，β=73.452(1)°，γ=69.372(1)°，V=1.837 00(8) nm3，Z=1，Mr=3 476.78，F(000)=1 538，μ=18.815 mm-1，Dc=3.143 mg·m-3，S=1.062，R1=0.046 2,wR2=0.138 7。化合物1的结构单元包含一个［PW12O40］3-多阴离子和四个3-PA配体，并通过［PW12O40］3-多阴离子和3-PA配体之间的氢键连接形成二维超分子层。化合物1在光催化还原Cr(Ⅵ)反应中展现出良好的光催化活性，并具有较好的结构稳定性和可循环利用性。

面向高效、高精度光学遥感图像目标检测应用,重点针对提升SSD(single shot multibox detector)模型对图像中聚集分布的小尺寸目标检测精度的难点,提出一种FFC-SSD(multi-scale feature fusion & clustering SSD)改进模型;设计目标框分组聚类(BGC)模块,采用分组聚类的方法获得更符合目标样本尺寸分布的默认目标框参数并给予小尺寸目标更多关注,以有效提升网络对目标位置信息的提取能力;设计反池化高效多尺度特征融合(MSFF)模块,以在增强模型目标特征提取能力的同时有效减小模型效率损耗。实验结果显示了所提模型对光学遥感图像目标检测的有效性与适用性,较好地实现了精度与效率的平衡,对小尺寸目标具有较高的检测精度。

通过水热合成方法, 以钼酸铵、氯化镍和4-氨基吡啶为原料成功合成了一个Keggin型多酸基超分子化合物H3［{H(4-AP)}6(PMoV6MoVI6O40)］ (4-AP=4-氨基吡啶)。该化合物的结构单元包含一个［PMoV6MoVI6O40］9-阴离子和6个质子化的配体。而［PMoV6MoVI6O40］9-阴离子与配体之间通过N(1)-H(1)…O(3)、N(2)-H(2A)…O(5)和N(2)-H(2B)…O(1)三种氢键相互作用, 进而形成二维超分子层。通过X射线单晶衍射、IR和粉末X射线衍射对其进行表征。晶体结构分析表明: 该标题化合物属于三方晶系, R-3空间群, a=2.191 2 (10) nm, b=2.191 2 (10) nm, c=1.042 3(5) nm, α=β=90°, γ=120°, V=4.333 8(4) nm3, Z=3, R1=0.036 2, wR2=0.095 6, 电催化性质研究表明该标题化合物对H2O2和K2Cr2O7具有良好的电催化还原效果, 以及对抗坏血酸具有良好的电催化氧化效果。

通过水热反应, 成功合成了一个草酸配体修饰的四核锆取代的夹心型硅钨-氧簇合物H12Na2［Zr4(μ3-O)2(μ2-OH)2(Ox)2(α-SiW10O37)2］·22H2O (Ox=oxalic acid)。该夹心型硅钨-氧簇是由两个{α-SiW10O37}簇块通过一个{Zr4(μ3-O)2(μ2-OH)2(Ox)2}簇连接构成的。通过X-射线单晶衍射、IR、TG以及元素分析对该簇合物进行表征。晶体结构分析表明: 该簇合物结晶于单斜晶系, P21/c空间群, a=2.132 2 (6) nm, b=1.271 6 (4) nm, c=2.223 1 (7) nm, β=110.933(4)°, V=5.629 9(3) nm3, Z=2, R1=0.061 5, wR2=0.164 4。电化学和电催化性质研究表明标题簇合物对NO-2的还原有很好的电催化效果。