Synthesis of Hard–Soft–Hard Triblock Copolymers, Poly(2-naphthyl glycidyl ether)-block-poly[2-(2-(2-methoxyethoxy)ethoxy)ethyl glycidyl ether]-block-poly(2-naphthyl glycidyl ether), for Solid Electrolytes

Construction of weakly solvating solid polymer electrolytes for high-voltage and stable lithium metal batteries

Industrial applications of in-situ polymerized solid-state electrolytes still face major challenges, such as low ionic conductivity, electrochemical instability, and incompatibility with high-voltage cathode. Herein, the fluorine-containing weakly solvating solid polymer electrolytes are designed to regulate the solvation structure, Li+ conductivity, and electrode/electrolyte interface. The strong electron-withdrawing effect and localization ability of fluorine atoms alter the electrostatic potential and charge distribution of the ether oxygen groups in monomer and solvent. This weakens the coordination between Li+ and the monomer/solvent while enhancing the coordination with the salt anion, leading to the formation of more contact ion pairs (CIPs) and aggregates (AGGs). This promotes the formation of inorganic-rich solid electrolyte interphase (SEI), enhancing the ionic conductivity of electrolytes and ameliorating the electrode/electrolyte interface. Furthermore, the introduction of fluorine lowers the HOMO of electrolyte, effectively improving its oxidative stability. Herein, a stable lithium stripping/deposition is achieved in Li||Li symmetric cells, maintaining 6420 h at 0.05 mA cm-2. Furthermore, the Li||LiCoO2 cells stably work 281 cycles with a capacity retention of 89.3 % at 0.5 C during a high voltage of 3-4.5 V. This strategy paves the way for the practicability of lithium metal batteries.

Highly Conductive Polyoxanorbornene-Based Polymer Electrolyte for Lithium-Metal Batteries

This present study illustrates the synthesis and preparation of polyoxanorbornene-based bottlebrush polymers with poly(ethylene oxide) (PEO) side chains by ring-opening metathesis polymerization for solid polymer electrolytes (SPE). In addition to the conductive PEO side chains, the polyoxanorbornene backbones may act as another ion conductor to further promote Li-ion movement within the SPE matrix. These results suggest that these bottlebrush polymer electrolytes provide impressively high ionic conductivity of 7.12 × 10-4 S cm-1 at room temperature and excellent electrochemical performance, including high-rate capabilities and cycling stability when paired with a Li metal anode and a LiFePO4 cathode. The new design paradigm, which has dual ionic conductive pathways, provides an unexplored avenue for inventing new SPEs and emphasizes the importance of molecular engineering to develop highly stable and conductive polymer electrolytes for lithium-metal batteries (LMB).

Lithium-Conducting Branched Polymers: New Paradigm of Solid-State Electrolytes for Batteries

The past decades have witnessed rapid development of lithium-based batteries. Significant research efforts have been progressively diverted from electrodes to electrolytes, particularly polymer electrolytes (PEs), to tackle the safety concern and promote the energy storage capability of batteries. To further increase the ionic conductivity of PEs, various branched polymers (BPs) have been rationally designed and synthesized. Compared with linear polymers, branched architectures effectively increase polymer segmental mobility, restrain crystallization, and reduce chain entanglement, thereby rendering BPs with greatly enhanced lithium transport. In this Mini Review, a diversity of BPs for PEs is summarized by scrutinizing their unique topologies and properties. Subsequently, the design principles for enhancing the physical properties, mechanical properties, and electrochemical performance of BP-based PEs (BP-PEs) are provided in which the ionic conduction is particularly examined in light of the Li⁺ transport mechanism. Finally, the challenges and future prospects of BP-PEs in this rapidly evolving field are outlined.

Poly(p-phenylene)s tethered with oligo(ethylene oxide): synthesis by Yamamoto polymerization and properties as solid polymer electrolytes

Salt-containing rigid-rod polyphenylenes tethered with ethylene oxide side chains form mechanically and thermally stable “molecular composite electrolytes” reaching high conductivity.

Flexible and low-k polymer featuring hard–soft-hybrid strategy

One of the main challenges for dielectric materials for advanced microelectronics is their high dielectric value and brittleness. In this study, we adopted a hard–soft-hybrid strategy and successfully introduced a hard, soft segment and covalent crosslinked structural unit into a hybridized skeleton via copolymerization of polydimethylsiloxane (PDMS), benzocyclobutene (BCB) and double-decker-shaped polyhedral silsesquioxanes (DDSQ) by a platinum-catalyzed hydrosilylation reaction, thus producing a random copolymer (PDBD) with a hybridized skeleton in the main chain. PDBD exhibited high molecular weight and thermal curing action without any catalyst. More importantly, the cured copolymer displayed high flexibility, high thermal stability and low dielectric constant, evidencing its potential applications in high-performance dielectric materials.

Hard–Soft-hybrid strategy is used to synthesize random copolymers with a hybridized main chain.

Covalently cross-linked polymer stabilized electrolytes with self-healing performance via boronic ester bonds

This article reported a facile fabrication of self-healing solid polymer electrolytes via boronic ester bonds.

Block copolymers for supercapacitors, dielectric capacitors and batteries

Block copolymer-based energy storage emerges as an active interdisciplinary research field. This topical review presents a survey of the recent advances in block copolymers for energy storage. In the first section, we introduce the background of electrochemical energy storage and block copolymer thermodynamics. In the second section, we discuss the current understandings of block copolymer chemistry, processing, pore size, and ionic conductivity. In the third section, we summarize the design principles and state-of-the-art applications of block copolymers in three energy storage devices, namely, supercapacitors, dielectric capacitors, and batteries. Lastly, we present our perspectives on future possible breakthroughs and associated challenges that are essential to propel the development of advanced block copolymers for energy storage. We expect the review to encourage innovative studies on integrating block copolymers into energy storage applications.

Monochromatic "Photoinitibitor"-Mediated Holographic Photopolymer Electrolytes for Lithium-Ion Batteries

A new polymer electrolyte based on holographic photopolymer is designed and fabricated. Ethylene carbonate (EC) and propylene carbonate (PC) are introduced as the photoinert substances. Upon laser-interference-pattern illumination, photopolymerization occurs within the constructive regions which subsequently results in a phase separation between the photogenerated polymer and unreacted EC-PC, affording holographic photopolymer electrolytes (HPEs) with a pitch of ≈740 nm. Interestingly, both diffraction efficiency and ionic conductivity increase with an augmentation of the EC-PC content. With 50 wt% of EC-PC, the diffraction efficiency and ionic conductivity are ≈60% and 2.13 × 10-4 S cm-1 at 30 °C, respectively, which are 60 times and 5 orders of magnitude larger than the electrolyte without EC-PC. Notably, the HPEs afford better anisotropy and more stable electrochemical properties when incorporating N,N-dimethylacrylamide. The HPEs exhibit good toughness under bending, excellent optical transparency under ambient conditions, and astonishing capabilities of reconstructing colored images. The HPEs here open a door to design flexible and transparent electronics with good mechanical, electrical, and optical functions.

High-Charge Density Polymerized Ionic Networks Boosting High Ionic Conductivity as Quasi-Solid Electrolytes for High-Voltage Batteries

Solid-state electrolytes are actively sought for their potential application in energy storage devices, especially lithium metal rechargeable batteries. However, one of the key challenges in the development of solid-state electrolytes is their lower ionic conductivity compared with that of liquid electrolytes (10^-2 S cm^-1 at room temperature), where a large gap still exists. Therefore, the pursuit of high ionic conductivity equal to that of liquid electrolytes remains the main objective for the design of solid-state electrolytes. Here, we show a series of high-charge density polymerized ionic networks as solid-state electrolytes that take inspiration from poly(ionic liquid)s. The obtained quasi-solid electrolyte slice displays an astonishingly high ionic conductivity of 5.89 × 10^-3 S cm^-1 at 25 °C (the highest conductivity among those of the state-of-art polymer gel electrolytes and polymer solid electrolytes) and ultrahigh decomposition potential, >5.2 V versus Li/Li⁺, which are attributed to the continuous ion transport channel formed by an ultrahigh ion density and an enhanced chemical stability endowed by highly cross-linked networks. The Li/LiFePO₄ and Li/LiCoO₂ batteries (3.0-4.4 V) assembled with the solid electrolytes show high stable capacities of around 155 and 130 mAh g^-1, respectively. In principle, our work breaks new ground for the design and fabrication of the solid-state electrolytes in various energy conversion devices.

Self-healing and shape-memory solid polymer electrolytes with high mechanical strength facilitated by a poly(vinyl alcohol) matrix

This article reports PVA-based electrolytes with supramolecular networks formed via quadruple hydrogen bonding for lithium-ion batteries.

Development of the PEO Based Solid Polymer Electrolytes for All-Solid State Lithium Ion Batteries

Solid polymer electrolytes (SPEs) have attracted considerable attention due to the rapid development of the need for more safety and powerful lithium ion batteries. The prime requirements of solid polymer electrolytes are high ion conductivity, low glass transition temperature, excellent solubility to the conductive lithium salt, and good interface stability against Li anode, which makes PEO and its derivatives potential candidate polymer matrixes. This review mainly encompasses on the synthetic development of PEO-based SPEs (PSPEs), and the potential application of the resulting PSPEs for high performance, all-solid-state lithium ion batteries.