A Gum‐Like Electrolyte: Safety of a Solid, Performance of a Liquid

Abstract

Lithium ion batteries (LIBs) with fl exibility [ 1,2 ] and safety are increasingly demanded and have become critical for the development of various industry sectors including electronics, electric vehicles, aircraft and biomedical electronics. [ 3 ] An ideal electrolyte for safe and fl exible LIBs should possess the high ionic conductivity of liquid electrolyte levels, good safety and mechancial properties of solid electrolyte materials, conformability/fl exibility and excellent contact/adhesion with electrodes and so on. However, it is a challenge to integrate these properties in one electrolyte and the existing electrolytes are facing various unsolved issues. [ 3,4 ] Specifi cally, solid polymer electrolytes (SPEs) are safe in essence; nonetheless, the low ionic conductivity and poor contact/adhesion at the electrolyte-electrode interfaces prevent the real applications of SPEs to commerical batteries. For liquid-state electrolytes, including ionic liquid electrolytes, the liquid attribute causes safety concerns, such as leakage or gasgenerating reactions at high temperature, [ 5 ] and low mechanical properties. Gel electrolytes are a promising solution for highperformance lithium ion batteries because they can simultaneously possess high ionic conductivity and good mechanical properties. [ 6 ] However, for existing gel electrolytes, the safety issues still exist because of the high content of liquid electrolyte and an unstable retention of the liquid electrolyte especially under deformations. [ 7 ] Addressing these problems is a critical challenge towards unlocking the vast potential of LIBs; in particular, safety is an increasing concern, as demonstrated by the recent grounding of the Boeing 787 due to battery safety problems. Currently, there are two main approaches to improve the safety of LIBs. The fi rst one is to replace the existing liquid electrolytes with safer electrolytes, such as solid polymer electrolytes (SPEs) or ionic liquid electrolytes. The second way is to introduce various sensors or additives for the commonly used liquid electrolytes, such as redox shuttles, [ 8 ] or polymerizable organics. [ 9 ] Unfortunately, though these methods could improve the safety of the LIBs, these electrolytes have their intrinsic disadvantages as introduced above. Moreover, as fl exibility is attracting more and more attention for new high-performance LIBs, [ 10 ] excellent performance stability as well as leakage-free behavior under various deformations are the most important factors for their applications. [ 11 ] It is noted that for fl exible/stretchable energy storage devices, not only good mechanical properties of the battery electrolytes are desired, but also a stable and effective electrolyte-electrode interface under deformation are highly required. [ 12 ] The aim of our work on the gum-like electrolyte reported in this communication is to achieve the ideal electrolyte properties described above. To that end, we specially designed a hybrid electrolyte with multi-network structures (see Figure 1 a)....

Composite electrolyte membranes incorporating viscous copolymers with cellulose for high performance lithium-ion batteries

“…To meet this increasing demand, advanced electrolyte materials, possessing high ionic conductivity, good safety and mechanical properties and excellent contact/adhesion with electrodes, are urgently needed [4]. For traditional organic electrolyte, excellent interfacial contact with electrodes and electrochemical performance make it possible for practical application, however, safety concerns have been raised due to the leakage and explosive nature of volatile organic electrolytes at high temperature (>60 o C) [5].…”

“…As the electrode/SPE interfaces are non-fluid solid/solid contacts, i.e., SPEs cannot fully infiltrate the electrode materials like liquid electrolytes, prolonged electrochemical cycle degradation becomes evident in all solid-state LIBs [4,19,20]. Considerable efforts have been devoted to mitigate the interfacial stability, such as adding or grafting a certain amount of ceramic powders (SiO 2 [21], Al 2 O 3 [22], ZnO [23], CeO [24], ZnAl 2 O 4 [25]) into the SPEs.…”

Deformable and Transparent Ionic and Electronic Conductors for Soft Energy Devices

“…[167] The schematic of the hybrid electrolyte is shown in Figure 8a. A liquid electrolyte (LiClO 4 in propylene carbonate) is used as the percolation network, which provides the pathway for the ions to migrate, giving rise to a high ionic conductivity of 3 × 10 −4 S cm −1 .…”

“…The work can be broadly categorized into hydrogel-and ionogel-based supercapacitors. Sáha and co-workers reported a sticky and [167] Copyright 2013, Wiley-VCH. c) Schematic representation of semicrystalline polymer microstructure when subjected to tensile deformation.…”

Toward Soft Skin‐Like Wearable and Implantable Energy Devices

“…In 2013, A gum-like hybrid electrolyte was presented with improved safety and stretchability. [58] This hybrid electrolyte consists of a double percolation network structure, in which a percolation network of a liquid electrolyte is supported by a network of solid particles and a strong entanglement network of polymer electrolyte (polyethylene oxide with LiClO 4 ). The gum-like hybrid electrolyte with liquid electrolyte content of ca.…”