Poly(ethylene oxide) (PEO) based materials are widely considered as promising candidates of polymer hosts in solid-state electrolytes for high energy density secondary lithium batteries. They have several specific advantages such as high safety, easy fabrication, low cost, high energy density, good electrochemical stability, and excellent compatibility with lithium salts. However, the typical linear PEO does not meet the production requirement because of its insufficient ionic conductivity due to the high crystallinity of the ethylene oxide (EO) chains, which can restrain the ionic transition due to the stiff structure especially at low temperature. Scientists have explored different approaches to reduce the crystallinity and hence to improve the ionic conductivity of PEO-based electrolytes, including blending, modifying and making PEO derivatives. This review is focused on surveying the recent developments and issues concerning PEO-based electrolytes for lithium-ion batteries.

Poly(ethylene oxide)-based electrolytes for lithium-ion batteries

Iron Catalysis in Organic Synthesis

In this review, state-of-the-art polymer electrolytes are discussed with respect to their electrochemical and physical properties for their application in lithium polymer batteries. We divide polymer electrolytes into the two large categories of solid polymer electrolytes and gel polymer electrolytes (GPE). The performance requirements and ion transfer mechanisms of polymer electrolytes are presented at first. Then, solid polymer electrolyte systems, including dry solid polymer electrolytes, polymer-in-salt systems (rubbery electrolytes), and single-ion conducting polymer electrolytes, are described systematically. Solid polymer electrolytes still suffer from poor ionic conductivity, which is lower than 10−5 S cm−1. In order to further improve the ionic conductivity, numerous new types of lithium salt have been studied and inorganic fillers have been incorporated into solid polymer electrolytes. In the section on gel polymer electrolytes, the types of plasticizer and preparation methods of GPEs are summarized. Although the ionic conductivity of GPEs can reach 10−3 S cm−1, their low mechanical strength and poor interfacial properties are obstacles to their practical application. Significant attention is paid to the incorporation of inorganic fillers into GPEs to improve their mechanical strength as well as their transport properties and electrochemical properties.

Polymer electrolytes for lithium polymer batteries

https://www.cell.com/trends/biotechnology/pdf/S0167-7799(13)00030-9.pdf

Antibacterial surfaces: the quest for a new generation of biomaterials.

The urgent need for safer batteries is leading research to all-solid-state lithium-based cells. To achieve energy density comparable to liquid electrolyte-based cells, ultrathin and lightweight solid electrolytes with high ionic conductivity are desired. However, solid electrolytes with comparable thicknesses to commercial polymer electrolyte separators (~10 μm) used in liquid electrolytes remain challenging to make because of the increased risk of short-circuiting the battery. Here, we report on a polymer–polymer solid-state electrolyte design, demonstrated with an 8.6-μm-thick nanoporous polyimide (PI) film filled with polyethylene oxide/lithium bis(trifluoromethanesulfonyl)imide (PEO/LiTFSI) that can be used as a safe solid polymer electrolyte. The PI film is nonflammable and mechanically strong, preventing batteries from short-circuiting even after more than 1,000 h of cycling, and the vertical channels enhance the ionic conductivity (2.3 × 10−4 S cm−1 at 30 °C) of the infused polymer electrolyte. All-solid-state lithium-ion batteries fabricated with PI/PEO/LiTFSI solid electrolyte show good cycling performance (200 cycles at C/2 rate) at 60 °C and withstand abuse tests such as bending, cutting and nail penetration. A nanoporous polyimide film filled with a solid polymer electrolyte has high ionic conductivity and high mechanical strength. An all-solid-state battery made with an approximately 10-μm-thick film shows good cyclability at 60 °C and no dendrite formation.

Ultrathin, flexible, solid polymer composite electrolyte enabled with aligned nanoporous host for lithium batteries.

Microporous polymer electrolyte based on PVDF/PEO star polymer blends for lithium ion batteries

Polymer electrolytes are envisioned to be promising alternatives to their liquid counterparts in lithium-ion batteries as they are able to address electrolyte inflammability and leakage issues. However, polymer electrolytes usually suffer from cracks or breakage, which could lead to short circuits and bring severe safety issues. Herein, we propose a paradigm to address these problems in which the polymer electrolyte is formed by a physically cross-linked network via ureidopyrimidinone (UPy) containing brush-like poly(ethylene glycol) chains. The formed novel polymer electrolyte is flexible and able to provide fast intrinsic self-healability and high stretchability. It can heal the cut damage within 2 hours under ambient conditions without any external stimulus and can be stretched to more than 20 times its length without breaking. Furthermore, the novel polymer electrolyte exhibits excellent interfacial stability with electrodes, resulting in high performance batteries with stable reversible electrochemical reaction and cycling.

A flexible, self-healing and highly stretchable polymer electrolyte via quadruple hydrogen bonding for lithium-ion batteries

Compared with liquid electrolytes, the solid polymer electrolyte (SPE), which possesses improved thermal and mechanical stability, is believed the broadest potential application for satisfying the ...

Dan He

Papers

Poly(ethylene oxide)-based electrolytes for lithium-ion batteries

Microporous polymer electrolyte based on PVDF/PEO star polymer blends for lithium ion batteries

A flexible, self-healing and highly stretchable polymer electrolyte via quadruple hydrogen bonding for lithium-ion batteries

Self-Healing Solid Polymer Electrolyte Facilitated by a Dynamic Cross-Linked Polymer Matrix for Lithium-Ion Batteries

Iron-catalyzed atom transfer radical polymerization