A Superior Polymer Electrolyte with Rigid Cyclic Carbonate Backbone for Rechargeable Lithium Ion Batteries

Abstract

The fabricating process of well-known Bellcore poly(vinylidene fluoride-hexafluoropropylene) (PVdF-HFP)-based polymer electrolytes is very complicated, tedious, and expensive owing to containing a large amount of fluorine substituents. Herein, a novel kind of poly(vinylene carbonate) (PVCA)-based polymer electrolyte is developed via a facile in situ polymerization method, which possesses the merits of good interfacial compatibility with electrodes. In addition, this polymer electrolyte presents a high ionic conductivity of 5.59 × 10 S cm and a wide electrochemical stability window exceeding 4.8 V vs Li/Li at ambient temperature. In addition, the rigid cyclic carbonate backbone of poly(vinylene carbonate) endows polymer electrolyte a superior mechanical property. The LiFeMnPO/graphite lithium ion batteries using this polymer electrolyte deliver good rate capability and excellent cyclability at room temperature. The superior performance demonstrates that the PVCA-based electrolyte via in situ polymerization is a potential alternative polymer electrolyte for high-performance rechargeable lithium ion batteries.

A Compact Gel Membrane Based on a Blend of PEO and PVDF for Dendrite‐Free Lithium Metal Anodes

“…The dependence of ionic conductivity of the PEO/PVDF‐based GM and the wet separator on different temperatures from 25 °C to 105 °C was illustrated in Figure a. The ionic conductivity at different temperature can be calculated using Equation (3) and the bulk resistance of the GM or the wet separator can be acquired from the intercept of the straight line on the real axis of EIS shown in Figure S3 . The ionic conductivity of the PEO/PVDF‐based GM increases with temperature and definitely accords with the Arrhenius ion conduction mechanism till 105 °C.…”

Microgravimetric and Spectroscopic Analysis of Solid−Electrolyte Interphase Formation in Presence of Additives

“…However, there is lack of information regarding the exact composition of the DPOP based SEI layer and we intend to address this aspect latter by means of XPS (see Section 2.2). The negligible mass reduction after drying of the SEI formed in VC can be related to the stable polymer product, resulting from the electropolymerization process of this additive …”

“…The extended transition zone in case of VC modified SEI layer can be related to the formation of a relatively thick porous polymer upper layer, wherein different fluorophosphates and LiF components are uniformly incorporated. These results correlate well with the microgravimetric data, displaying once more the stable SEI formed in presence of VC, due to the rigid mechanical behavior of the polymerized VC . In addition, the very short transition to the LiF rich part of SEI in case of reference sample indicates insufficiency or lack of stability of the organic rich overlayer formed in the absence of additive.…”

“…The negligible mass reduction after drying of the SEI formed in VC can be related to the stable polymer product, resulting from the electropolymerization process of this additive. [27] A high number of studies have shown that SEI has a complex structure, involving decomposition products with organic and inorganic origin. [1][2][3][4][5][6][7] Organic SEI components can potentially induce viscoelastic behavior, while the presence of inorganic compounds is associated with a rigid structure.…”

“…These results correlate well with the microgravimetric data, displaying once more the stable SEI formed in presence of VC, due to the rigid mechanical behavior of the polymerized VC. [27] In addition, the very short transition to the LiF rich part of SEI in case of reference sample indicates insufficiency or lack of stability of the organic rich overlayer formed in the absence of additive. This observation indicates a clear association with the microgravimetric behavior of SEIs investigated by EQCM.…”