Data_Sheet_1_SiC Nanofibers as Long-Life Lithium-Ion Battery Anode Materials.DOC

<p>The development of high energy lithium-ion batteries (LIBs) has spurred the designing and production of novel anode materials to substitute currently commercial using graphitic materials. Herein, twisted SiC nanofibers toward LIBs anode materials, containing 92.5 wt% cubic β-SiC and 7.5 wt% amorphous C, were successfully synthesized from resin-silica composites. The electrochemical measurements showed that the SiC-based electrode delivered a stable reversible capacity of 254.5 mAh g⁻¹ after 250 cycles at a current density of 0.1 A g⁻¹. It is interesting that a high discharge capacity of 540.1 mAh g⁻¹ was achieved after 500 cycles at an even higher current density of 0.3 A g⁻¹, which is higher than the theoretical capacity of graphite. The results imply that SiC nanomaterials are potential anode candidate for LIBs with high stability due to their high structure stability as supported with the transmission electron microscopy images.</p

Stabilizing Li₁₀SnP₂S₁₂/Li Interface via an in Situ Formed Solid Electrolyte Interphase Layer

Despite the extremely high ionic conductivity, the commercialization of Li₁₀GeP₂S₁₂-type materials is hindered by the poor stability against Li metal. Herein, to address that issue, a simple strategy is proposed and demonstrated for the first time, i.e., in situ modification of the interface between Li metal and Li₁₀SnP₂S₁₂ (LSPS) by pretreatment with specific ionic liquid and salts. X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy results reveal that a stable solid electrolyte interphase (SEI) layer instead of a mixed conducting layer is formed on Li metal by adding 1.5 M lithium bis­(trifluoromethanesulfonyl)­imide (LiTFSI)/<i>N</i>-propyl-<i>N</i>-methyl pyrrolidinium bis­(trifluoromethanesulfonyl)­imide (Pyr₁₃TFSI) ionic liquid, where ionic liquid not only acts as a wetting agent but also improves the stability at the Li/LSPS interface. This stable SEI layer can prevent LSPS from directly contacting the Li metal and further decomposition, and the Li/LSPS/Li symmetric cell with 1.5 M LiTFSI/Pyr₁₃TFSI attains a stable cycle life of over 1000 h with both the charge and discharge voltages reaching about 50 mV at 0.038 mA cm^–2. Furthermore, the effects of different Li salts on the interfacial modification is also compared and investigated. It is shown that lithium bis­(fluorosulfonyl) imide (LiFSI) salt causes the enrichment of LiF in the SEI layer and results in a higher resistance of the cell upon a long cycling life