Jin Nie

Single Lithium‐Ion Conducting Polymer Electrolytes Based on a Super‐Delocalized Polyanion

A novel single lithium-ion (Li-ion) conducting polymer electrolyte is presented that is composed of the lithium salt of a polyanion, poly[(4-styrenesulfonyl)(trifluoromethyl(S-trifluoromethylsulfonylimino)sulfonyl)imide] (PSsTFSI(-)), and high-molecular-weight poly(ethylene oxide) (PEO). The neat LiPSsTFSI ionomer displays a low glass-transition temperature (44.3 °C; that is, strongly plasticizing effect). The complex of LiPSsTFSI/PEO exhibits a high Li-ion transference number (tLi (+) =0.91) and is thermally stable up to 300 °C. Meanwhile, it exhibits a Li-ion conductivity as high as 1.35×10(-4)  S cm(-1) at 90 °C, which is comparable to that for the classic ambipolar LiTFSI/PEO SPEs at the same temperature. These outstanding properties of the LiPSsTFSI/PEO blended polymer electrolyte would make it promising as solid polymer electrolytes for Li batteries.

Impact of the functional group in the polyanion of single lithium-ion conducting polymer electrolytes on the stability of lithium metal electrodes

A novel single lithium-ion (Li-ion) conducting polymer electrolyte composed of lithium poly[(4-styrenesulfonyl)(fluorosulfonyl)imide] (LiPSFSI) and poly(ethylene oxide) (PEO) exhibits a high Li-ion transference number (tLi+ = 0.90) and sufficient electrochemical stability for use in Li batteries. The ionic conductivities of the LiPSFSI/PEO blended polymer electrolytes are higher than those of the lithium poly(4-styrenesulfonate) (LiPSS)/PEO electrolyte and are comparable to those of the lithium poly[(4-styrenesulfonyl)(trifluoromethanesulfonyl)imide] (LiPSTFSI)/PEO electrolyte in the temperature range of 25–90 °C. More importantly, the complex of LiPSFSI/PEO exhibits excellent interfacial compatibility with the Li metal electrode compared to both those of the LiPSS/PEO and LiPSTFSI/PEO electrolytes.

A new Na[(FSO2)(n-C4F9SO2)N]-based polymer electrolyte for solid-state sodium batteries

To improve the safety of sodium (Na) batteries, we first report a new solid polymer electrolyte (SPE), composed of sodium (fluorosulfonyl)(n-nonafluorobutanesulfonyl)imide (Na[(FSO2)(n-C4F9SO2)N], NaFNFSI) and poly(ethylene oxide) (PEO), which is prepared by a facile solution-casting method. The NaFNFSI/PEO (EO/Na+ = 15) blended polymer electrolyte exhibits a relatively high ionic conductivity of 3.36 × 10−4 S cm−1 at 80 °C, sufficient thermal stability (>300 °C) and anodic electrochemical stability (≈4.87 V vs. Na+/Na) for application in solid-state Na batteries. Most importantly, the NaFNFSI-based SPE can not only deliver excellent chemical and electrochemical stability with Na metal, but can also display good cycling and current-rate performances for the Na|SPE|NaCu1/9Ni2/9Fe1/3Mn1/3O2 cell. All of these outstanding properties would make the NaFNFSI-based SPE promising as a candidate for application in solid-state Na batteries.