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Tin (Sn)-based materials are potential alternatives to the commercial graphite anode for next-generation Li-ion batteries (LIBs) due to their high theoretical capacity. However, the poor cyclic stability, originating from the large volumetric changes during charge/discharge process, hinder their practical utilization. Herein, we have successfully prepared a Sn-based metal-organic framework (MOF, Sn-PMA), and explored as potential anode materials in LIBs. Benefiting from its layered structure and efficient electron transport channels, Sn-PMA electrodes deliver a high initial capacity of 1567 mAh g−1, at 100 mA g−1, and maintained a reversible capacity of 707 mAh g−1, at 800 mA g−1, after 400 cycles. Furthermore, the detailed post-electrochemical structural, morphological and compositional analysis is carried out to unveil the structural changes and Li-ion storage mechanism of electrodes. Ex-situ XRD and XPS results revealed that, in Sn-PMA electrode, O atom, coordinated to the Sn atom, exhibited higher electronegativity, served as major Li-ion storage site and rendered excellent cyclic stability due to a stable structure. Kinetic analyses reveal that the excellent performance of the Sn-PMA is typical attributed to the pseudocapacitive contribution induced by the special porous structure.

Since 5 V lithium ion batteries have attracted more and more attentions and are deemed to be an important tendency in the future, the matched design of the separators has also become a necessary and significant work. In this work, the lithium ionic conducting glass ceramic Li1.5Al0.5Ge1.5(PO4)3-polypropylene (PP) based inorganic–organic composite separator (LAGP-PP) is prepared. Compared with the pristine PP separator, the LAGP-PP separator owns enhanced thermal stability and wettability. Meanwhile, the LAGP-PP separator shows higher ion conductivity than the traditional Al2O3 coated PP separator due to the more facile lithium ion diffusion channels in the coating layer. The superior C-rate capacity and cyclability in the LiNi0.5Mn1.5O4 based 5 V lithium ion batteries indicate that the LAGP-PP separator is a good alternative for the traditional inert inorganic ceramic coated polyolefin separators and is a kind of promising candidate separator for the high voltage lithium ion batteries.

Although current collectors take up more weight than active materials in most lithium ion battery cells, so far research has been focused mainly on improving gravimetric capacities of active materials. To address this issue of improving gravimetric capacities based on overall cell components, we develop freestanding nanocomposites made of carbon nanofibers (CNFs) and silicon nanowires (SiNWs) as metal current collector-free anode platforms. Intrinsically large capacities of SiNWs as active materials in conjunction with the light nature of freestanding CNF films allow the nanocomposites to achieve 3–5 times improved gravimetric capacities compared to what have been reported in the literature. Moreover, three-dimensional porous structures in the CNF films facilitate increased mass loadings of SiNWs when compared to flat substrates and result in good cycle lives over 40 cycles. This type of nanocomposite cell suggests that 3D porous platforms consisting of light nanomaterials can provide for higher gravimetric and areal capacities when compared to conventional battery cells based on flat, heavy metal substrates.