Progress in Solid Polymer Electrolytes for Lithium‐Ion Batteries and Beyond

Abstract

the volume expansion of electrodes, poor impact resistance, high potential for gas production, easy corrosion of aluminum foil and oxidation of copper foil. Liquid electrolytes show poor compatibility with electrodes in some potential high-energy batteries. Other drawbacks of liquid electrolytes derive from the unstable longterm life cycle and poor performance in restraining the growth of lithium dendrites in LIBs, especially when lithium metal is used as an anode. Some potential cathodes, including transition metals, polysulfides in sulfur electrodes, and organic electrodes, tend to dissolve in liquid electrolytes, hindering the development of next-generation batteries. [1][2][3][4] Solid polymer electrolytes (SPEs) are considered a prospective approach to solving the above problems. [4] An alkali metal salt and polymer host, which plays a role as a solid matrix, form SPEs without additional organic liquid solvents. [5] Several outstanding advantages have been produced by SPEs over conventional liquid electrolytes such as low flammability, low electrolytes leakage, safety, high flexibility, and high stability between the electrode and electrolytes, etc. [6] Furthermore, SPEs possess excellent advantages over inorganic solid electrolytes, such as flexibility, light weight, ease of processing, suitability for large-scale manufacturing, and strong adhesion to electrodes. More importantly, the flexibility of polymer structural design and the suitability of various lithium salts and functional fillers provide many options for SPE design. [6][7][8] Among SPEs, high molecular weight polyethylene oxide (PEO)-based SPEs are commonly considered to be the finest candidates for polymer matrices due to their solvation power and complexation ability. [9] Wright et al. discovered that PEO can be used as a conductive matrix for alkali metal ions. [10,11] In 1983, Armand et al. reported the first PEO/Li + dry SPE system for LIBs (≈10 −4 S cm −1 at 40-60 °C). [12] Their pioneering work constituted a major breakthrough in the research on solid-state lithium-ion batteries (SSLIBs). Since then, polymers have attracted widespread attention as electrolytes for rechargeable SSLIBs. [8,[12][13][14] In LIBs, the SPE acts as an ion-conducting medium operating between the anode and cathode, and it plays the role of an electronically insulating separator. SPEs that meet these criteria should have six characteristics. [5][6][7][8] i) High ionic conductivity (σ) and high Li + transference numbers (t Li+ ). The polymers of SPEs must be able to dissolve sufficient amounts of lithium Solid-state polymer electrolytes (SPEs) for high electrochemical performance lithium-ion batteries have received considerable attention due to their unique characteristics; they are not prone to leakage, and they exhibit low flammability, excellent processability, good flexibility, high safety levels, and superior thermal stability. However, current SPEs are far from commercialization, mainly due to the low ionic conductivity, low Li + transference number (t Li+ ), ...

Are Polymer‐Based Electrolytes Ready for High‐Voltage Lithium Battery Applications? An Overview of Degradation Mechanisms and Battery Performance

“…Owing to the mentioned potential benefits of polymer electrolytes (safety, processability, energy density) and the current attention towards high‐energy lithium batteries, polymer electrolytes are experiencing a renewed interest, with almost one thousand research articles and over 50 reviews published in only the last five years (source Web of Science). Among these, several reviews describe the general progress in SSEs, [ 63–70 ] or in specific classes of polymer electrolytes [ 14,71–81 ]…”

“…Owing to the mentioned potential benefits of polymer electrolytes (safety, processability, energy density) and the current attention towards high-energy lithium batteries, polymer electrolytes are experiencing a renewed interest, with almost one thousand research articles and over 50 reviews published in only the last five years (source Web of Science). Among these, several reviews describe the general progress in SSEs, [63][64][65][66][67][68][69][70] or in specific classes of polymer electrolytes [14,[71][72][73][74][75][76][77][78][79][80][81] Certain reviews have specifically focused on the interfaces in solid-state batteries [82][83][84][85] and, particularly, on the issues related to the use of lithium metal anodes. [39,[86][87][88] Correspondingly, only a few recent reviews are focused on the cathode interface and the possible application in HVLP batteries.…”

Ionic Liquid@Metal-Organic Framework as a Solid Electrolyte in a Lithium-Ion Battery: Current Performance and Perspective at Molecular Level

“…Battery experts also anticipate the transition to alloyed silicon and silicon oxide, SiO x , because of their higher specific capacities compared to carbon-based anodes [ 14 , 15 , 16 , 17 , 18 ]. Although the development of electrode materials for LIBs is actively progressing [ 19 , 20 , 21 , 22 , 23 ], research in electrolyte has also gained interest from both academic and industry practitioners [ 24 , 25 , 26 , 27 ]. One of the main components of LIBs that plays an important role is electrolytes.…”

Percolated Sulfide in Salt‐Concentrated Polymer Matrices Extricating High‐Voltage All‐Solid‐State Lithium‐metal Batteries

“…When liquid electrolytes are substituted by solid electrolytes, whether polymers or inorganics, the safety risks can significantly be lowered. [4,5] Therefore, the development of all-solid-state lithium-metal batteries (ASLMBs) is one of the ultimate solutions to address the safety issue as well as the energy density of the battery.…”