锂离子电池聚合物电解质研究进展

综述了二次锂离子电池聚合物电解质的最新研究进展,对不同类型的聚合物电解质按其基体进行分类,包括常见的几种聚合物基体以及近年来发展起来的几种新型聚合物基体。对于每类基体相关的研究成果,主要关注的是电化学性能。对一些性能优异的聚合物电解质体系及其相应的制备方法,给出了较为全面的概述。与使用液体有机电解质的二次锂离子电池相比...     

锂离子电池用有机电解液和聚合物电解质的研究进展

从导电锂盐、有机溶剂和添加剂三个方面详细综述了锂离子电池用有机电解液的研究进展。同时针对聚合物电解质的组成、结构和性能的差异，将其分为四类，阐述了它们的优缺点及其在锂离子电池中的应用与研究进展。最后展望了电解质的发展前景。     

Lithium-Ion Battery Separators for Ionic-Liquid Electrolytes: A Review

Ionic liquids (ILs) are widely studied as a safer alternative electrolyte for lithium-ion batteries. The properties of IL electrolytes compared to conventional electrolytes make them more thermally stable, but they also have poor wetting with commercial separators. In a lithium-ion battery, the electrolyte should completely wet out the separator and electrodes to reduce the cell internal resistance. Investigations of cell materials with IL electrolytes have shown that the wetting issues in IL–electrolyte cells are most likely due to poor separator compatibility, not electrode compatibility. A compatible separator must be developed before IL electrolytes can be used in commercial lithium-ion batteries. Herein, separators for IL electrolytes, including commercial and novel separators, are reviewed. Separators with different processing methods, polymers, additives, and different IL electrolytes are considered. Collated, the separator studies show a strong correlation between ionic conductivity and membrane porosity, even more than the electrolyte type. The challenge of a suitable separator for IL electrolytes is not solved yet. Herein, it is revealed that a separator for IL electrolytes will most likely require a combination of high thermal and mechanical stability polymer, ceramic additives, and an optimized manufacturing process.     

Low-Temperature Fabrication of Bulk-Type All-Solid-State Lithium-Ion Battery Utilizing Nanosized Garnet Solid Electrolytes

Garnet-type Li₇La₃Zr₂O₁₂ (LLZ) materials are attracting attention as solid electrolytes (SEs) in oxide-based all-solid-state batteries (ASSBs) owing to their high ionic conductivity. Although the electrochemical stability of LLZ against Li metal is demonstrated with possible high energy density, high-temperature sintering above 1000 °C, which is required to achieve high Li-ion conductivity, results in the formation of insulating impurities at the electrode–electrolyte interfaces. Here, nanosized fine-particle samples of Ta-substituted Li_6.5La₃Zr_1.5Ta_0.5O₁₂ (LLZT) are successfully prepared at a remarkably low temperature of 400 °C utilizing an amorphous precursor oxide. The dense LLZT SE sintered by hot pressing at 500 °C shows room-temperature Li-ion conductivity of 1.03 × 10⁻⁴ S cm⁻¹ without any additives. In addition, the bulk-type NCM–graphite full battery cell fabricated with the LLZT fine particles through a hot-pressing sintering method at 550 °C exhibits a good charge–discharge performance at room temperature with the bulk-type areal discharge capacity of 0.831 mAh cm⁻². The nanosized garnet SE strategy demonstrated in this study paves the way for the formation of oxide-based ASSBs by low-temperature sintering.     

全固态锂离子电池正极界面的研究进展

全固态锂离子电池以其高能量密度和高安全性成为具有广泛应用前景的下一代储能技术。然而,全固态锂离子电池的容量过低和寿命过短限制了其在储能领域的应用。其中,正极材料(活性材料、电子导电剂、离子导电剂及固态电解质等)固-固界面稳定性不佳限制了全固态锂离子电池的容量利用率和循环寿命。综上,介绍和讨论了正极材料固-固界面稳定性及优化方法,包括化学稳定性、电化学稳定性、机械稳定性和热稳定性等,同时归纳了常用的全固态锂离子电池正极材料固-固界面优化方法,为全固态锂离子电池的开发和应用提供参考。     

Single-Ion Polymer Electrolyte Based on Lithium-Rich Imidazole Anionic Porous Aromatic Framework for High Performance Lithium-Ion Batteries

The low ionic conductivity and Li⁺ transference number ($t_{L{i}^{+}}$) of solid polymer electrolytes (SPEs) seriously hinder their application in lithium-ion batteries (LIBs). In this study, a novel single-ion lithium-rich imidazole anionic porous aromatic framework (PAF-220-Li) is designed. The abundant pores in PAF-220-Li are conducive to the Li⁺ transfer. Imidazole anion has low binding force with Li⁺. The conjugation of imidazole and benzene ring can further reduce the binding energy between Li⁺ and anions. Thus, only Li⁺ moved freely in the SPEs, remarkably reducing the concentration polarization and inhibiting lithium dendrite growth. PAF-220-quasi-solid polymer electrolyte (PAF-220-QSPE) is prepared through solution casting of Bis(trifluoromethane)sulfonimide lithium (LiTFSI) infused PAF-220-Li and Poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP), and possessed excellent electrochemical performance. The electrochemical property are further improved by preparing all-solid polymer electrolyte (PAF-220-ASPE) via pressing-disc method, which has a high Li⁺ conductivity of 0.501 mS cm⁻¹ and $t_{L{i}^{+}}$ of 0.93. The discharge specific capacity at 0.2 C of Li//PAF-220-ASPE//LFP reached 164 mAh g⁻¹, and the capacity retention rate is 90% after 180 cycles. This study provided a promising strategy for SPE with single-ion PAFs to achieve high-performance solid-state LIBs.     

Advanced Matrixes for Binder-Free Nanostructured Electrodes in Lithium-Ion Batteries

Commercial lithium-ion batteries (LIBs), limited by their insufficient reversible capacity, short cyclability, and high cost, are facing ever-growing requirements for further increases in power capability, energy density, lifespan, and flexibility. The presence of insulating and electrochemically inactive binders in commercial LIB electrodes causes uneven active material distribution and poor contact of these materials with substrates, reducing battery performance. Thus, nanostructured electrodes with binder-free designs are developed and have numerous advantages including large surface area, robust adhesion to substrates, high areal/specific capacity, fast electron/ion transfer, and free space for alleviating volume expansion, leading to superior battery performance. Herein, recent progress on different kinds of supporting matrixes including metals, carbonaceous materials, and polymers as well as other substrates for binder-free nanostructured electrodes in LIBs are summarized systematically. Furthermore, the potential applications of these binder-free nanostructured electrodes in practical full-cell-configuration LIBs, in particular fully flexible/stretchable LIBs, are outlined in detail. Finally, the future opportunities and challenges for such full-cell LIBs based on binder-free nanostructured electrodes are discussed.     

In Situ Construction Channels of Lithium-Ion Fast Transport and Uniform Deposition to Ensure Safe High-Performance Solid Batteries

Solid-state lithium-ion batteries (SLIBs) are the promising development direction for future power sources because of their high energy density and reliable safety. To optimize the ionic conductivity at room temperature (RT) and charge/discharge performance to obtain reusable polymer electrolytes (PEs), polyvinylidene fluoride (PVDF), and poly(vinylidene fluoride-hexafluoro propylene) (P(VDF-HFP)) copolymer combined with polymerized methyl methacrylate (MMA) monomers are used as substrates to prepare PE (LiTFSI/OMMT/PVDF/P(VDF-HFP)/PMMA [LOPPM]). LOPPM has interconnected lithium-ion 3D network channels. The organic-modified montmorillonite (OMMT) is rich in the Lewis acid centers, which promoted lithium salt dissociation. LOPPM PE possessed high ionic conductivity of 1.1 × 10⁻³ S cm⁻¹ and a lithium-ion transference number of 0.54. The capacity retention of the battery remained 100% after 100 cycles at RT and 0.5 C. The initial capacity of one with the second-recycled LOPPM PE is 123.9 mAh g⁻¹. This work offered a feasible pathway for developing high-performance and reusable LIBs.     

Role of Bicontinuous Structure in Elastomeric Electrolytes for High-Energy Solid-State Lithium-Metal Batteries

Solid-state lithium (Li)-metal batteries (LMBs) are garnering attention as a next-generation battery technology that can surpass conventional Li-ion batteries in terms of energy density and operational safety under the condition that the issue of uncontrolled Li dendrite is resolved. In this study, various plastic crystal-embedded elastomer electrolytes (PCEEs) are investigated with different phase-separated structures, prepared by systematically adjusting the volume ratio of the phases, to elucidate the structure-property-electrochemical performance relationship of the PCEE in the LMBs. At an optimal volume ratio of elastomer phase to plastic-crystal phase (i.e., 1:1), bicontinuous-structured PCEE, consisting of efficient ion-conducting, plastic-crystal pathways with long-range connectivity within a crosslinked elastomer matrix, exhibits exceptionally high ionic conductivity (≈10⁻³ S cm⁻¹) at 20 °C and excellent mechanical resilience (elongation at break ≈ 300%). A full cell featuring this optimized PCEE, a 35 µm thick Li anode, and a high loading LiNi_0.83Mn_0.06Co_0.11O₂ (NMC-83) cathode delivers a high energy density of 437 Wh kg_{anode+cathode+electrolyte}⁻¹. The established structure–property–electrochemical performance relationship of the PCEE for solid-state LMBs is expected to inform the development of the elastomeric electrolytes for various electrochemical energy systems.     

Nacre-Inspired Composite Electrolytes for Load-Bearing Solid-State Lithium-Metal Batteries

Solid-state lithium-metal batteries with solid electrolytes are promising for next-generation energy-storage devices. However, it remains challenging to develop solid electrolytes that are both mechanically robust and strong against external mechanical load, due to the brittleness of ceramic electrolytes and the softness of polymer electrolytes. Herein, a nacre-inspired design of ceramic/polymer solid composite electrolytes with a “brick-and-mortar” microstructure is proposed. The nacre-like ceramic/polymer electrolyte (NCPE) simultaneously possesses a much higher fracture strain (1.1%) than pure ceramic electrolytes (0.13%) and a much larger ultimate flexural modulus (7.8 GPa) than pure polymer electrolytes (20 MPa). The electrochemical performance of NCPE is also much better than pure ceramic or polymer electrolytes, especially under mechanical load. A 5 × 5 cm² pouch cell with LAGP/poly(ether-acrylate) NCPE exhibits stable cycling with a capacity retention of 95.6% over 100 cycles at room temperature, even undergoes a large point load of 10 N. In contrast, cells based on pure ceramic and pure polymer electrolyte show poor cycle life. The NCPE provides a new design for solid composite electrolyte and opens up new possibilities for future solid-state lithium-metal batteries and structural energy storage.     

Self-Repairable Silicon Anodes Using a Multifunctional Binder for High-Performance Lithium-Ion Batteries

Despite of extremely high theoretical capacity of Si (3579 mAh g⁻¹), Si anodes suffer from pulverization and delamination of the electrodes induced by large volume change during charge/discharge cycles. To address those issues, herein, self-healable and highly stretchable multifunctional binders, polydioxythiophene:polyacrylic acid:phytic acid (PEDOT:PAA: PA, PDPP) that provide Si anodes with self-healability and excellent structural integrity is designed. By utilizing the self-healing binder, Si anodes self-repair cracks and damages of Si anodes generated during cycling. For the first time, it is demonstrated that Si anodes autonomously self-heal artificially created cracks in electrolytes under practical battery operating conditions. Consequently, this self-healable Si anode can still deliver a reversible capacity of 2312 mAh g⁻¹ after 100 cycles with remarkable initial Coulombic efficiency of 94%, which is superior to other reported Si anodes. Moreover, the self-healing binder possesses enhanced Li-ion diffusivity with additional electronic conductivity, providing excellent rate capability with a capacity of 2084 mAh g⁻¹ at a very high C-rate of 5 C.     

Exploiting Zirconium-Based Metallic Glass Thin Films for Anode-Free Lithium-Ion Batteries and Lithium Metal Batteries With Ultra-Long Cycling Life

Coating Zr-based metallic glass, Zr₅₃Cu₃₁Ni₁₁Al₅ (Zr-MG), on a Cu current collector (CC) and Li metal anode (LMA) significantly improves the cycle performance of both types of Li-ion batteries, namely, anode-free Li-ion batteries (AFLBs) and Li metal batteries (LMB). The inherent isotropy and homogeneity of the Zr-MG significantly improve the surface uniformity of the CC and LMA. A 12 nm-thick Zr-MG thin film coating on the CC reduces the overpotential in the AFLB, leading to a more uniform Li plating morphology. The Li film covers almost the entire surface of the Zr-CC, whereas it only covers ≈75% of the bare CC during charging. An LFP||Zr-CC full-cell exhibits a capacity retention of 63.6% after the 100th cycle, with an average CE of 99.55% at a 0.2 C rate. In the case of the LMB, a 12 nm-thick Zr-MG thin film-coated LMA (Zr-LMA) exhibits a stable capacity of up to 1500 cycles. An LFP||Zr-LMA full-cell exhibits capacity retention and CE after 1500 cycles of 66.6% and 99.97%, respectively, at a 1 C rate. Zirconium-MG thin films with atomic-level uniformity, outstanding corrosion resistance, lithiophilic characteristics, and high diffusivity result in superior AFLB and LMB performances.     

A Uniform Self-Reinforced Organic/Inorganic Hybrid SEI Chelation Strategy on Microscale Silicon Surfaces for Stable-Cycling Anodes in Lithium-Ion Batteries

A promising anode material for Li-ion batteries, silicon (Si) suffers from volume expansion-induced pulverization and solid electrolyte interface (SEI) instability. Microscale Si with high tap density and high initial Coulombic efficiency (ICE) has become a more anticipated choice, but it will exacerbate the above issues. In this work, the polymer polyhedral oligomeric silsesquioxane-lithium bis (allylmalonato) borate (PSLB) is constructed by in situ chelation on microscale Si surfaces via click chemistry. This polymerized nanolayer has an “organic/inorganic hybrid flexible cross-linking” structure that can accommodate the volume change of Si. Under the stable framework formed by PSLB, a large number of oxide anions on the chain segment preferentially adsorb LiPF₆ and further induce the integration of inorganic-rich, dense SEI, which improves the mechanical stability of SEI and provides accelerated kinetics for Li⁺ transfer. Therefore, the Si4@PSLB anode exhibits significantly enhanced long-cycle performance. After 300 cycles at 1 A g⁻¹, it can still provide a specific capacity of 1083 mAh g⁻¹. Cathode-coupled with LiNi_0.9Co_0.05Mn_0.05O₂ (NCM90) in the full cell retains 80.8% of its capacity after 150 cycles at 0.5 C.     

Benchmarking the Effect of Particle Size on Silicon Anode Materials for Lithium-Ion Batteries (Small 42/2023)

High-capacity silicon has been regarded as one of the most promising anodes for high-energy lithium-ion batteries. However, it suffers from severe volume expansion, particle pulverization, and repeated solid electrolyte interphase (SEI) growth, which leads to rapid electrochemical failure, while the particle size also plays key role here and its effects remain elusive. In this paper, through multiple-physical, chemical, and synchrotron-based characterizations, the evolutions of the composition, structure, morphology, and surface chemistry of silicon anodes with the particle size ranging from 50 to 5 µm upon cycling are benchmarked, which greatly link to their electrochemical failure discrepancies. It is found that the nano- and micro-silicon anodes undergo similar crystal to amorphous phase transition, but quite different composition transition upon de-/lithiation; at the same time, the nano- and 1 µm-silicon samples present obviously different mechanochemical behaviors from the 5 µm-silicon sample, such as electrode crack, particle pulverization/crack as well as volume expansion; in addition, the micro-silicon samples possess much thinner SEI layer than the nano-silicon samples upon cycling, and also differences in SEI compositions. It is hoped this comprehensive study and understanding should offer critical insights into the exclusive and customized modification strategies to diverse silicon anodes ranging from nano to microscale.     

锂离子电池玻璃态电解质导电机理的研究进展

锂离子电池玻璃态电解质同晶体型电解质相比较具有导电性各向同性、锂离子电导率高等诸多优点, 开发在室温下具有较高的离子电导率及良好的化学、电化学稳定性的玻璃态电解质材料已经成为锂离子电池领域的重要研究方向之一。本文介绍了各种玻璃态电解质体系的导电特性及导电机理, 并重点分析与讨论混合网络形成体效应在一些典型玻璃态电解质体系中的微观作用机理。本文还总结了混合网络形成体效应在玻璃态电解质中发生的前提条件, 并指出深入研究玻璃态电解质的导电机理对开发出具有优异电化学性能的无机非晶固态电解质体系具有重要的指导意义。     

Advanced Composite Solid Electrolytes for Lithium Batteries: Filler Dimensional Design and Ion Path Optimization

Composite solid electrolytes are considered to be the crucial components of all-solid-state lithium batteries, which are viewed as the next-generation energy storage devices for high energy density and long working life. Numerous studies have shown that fillers in composite solid electrolytes can effectively improve the ion-transport behavior, the essence of which lies in the optimization of the ion-transport path in the electrolyte. The performance is closely related to the structure of the fillers and the interaction between fillers and other electrolyte components including polymer matrices and lithium salts. In this review, the dimensional design of fillers in advanced composite solid electrolytes involving 0D–2D nanofillers, and 3D continuous frameworks are focused on. The ion-transport mechanism and the interaction between fillers and other electrolyte components are highlighted. In addition, sandwich-structured composite solid electrolytes with fillers are also discussed. Strategies for the design of composite solid electrolytes with high room temperature ionic conductivity are summarized, aiming to assist target-oriented research for high-performance composite solid electrolytes.     

3D-Printed Thermoplastic Polyurethane Electrodes for Customizable,Flexible Lithium-Ion Batteries with an Ultra-Long Lifetime

3D printing technology has demonstrated great potential in fabricating flexible and customizable high-performance batteries, which are highly desired in the forthcoming intelligent and ubiquitous energy era. However, a significant performance gap, especially in cycling stability, still exists between the 3D-printed and conventional electrodes, seriously limiting the practical applications of 3D-printed batteries. Here, for the first time, a series of thermoplastic polyurethane (TPU)-based 3D-printed electrodes is developed via fused deposition modeling for flexible and customizable high-performance lithium-ion batteries. The TPU-based electrode filaments in kilogram order are prepared via a facile extrusion method. As a result, the electrodes are well-printed with high dimensional accuracy, flexibility, and mechanical stability. Notably, 3D-printed TPU-LFP electrodes exhibit a capacity retention of 100% after 300 cycles at 1C, which is among the best cycling performance of all the reported 3D-printed electrodes. Such excellent performance is associated with the superb stress cushioning properties of the TPU-based electrodes that can accommodate the volume change during the cycling and thus significantly prevent the collapse of 3D-printed electrode structures. The findings not only provide a new avenue to achieve customizable and flexible batteries but also guide a promising way to erase the performance gap between 3D-printed and conventional lithium-ion batteries.     

High‐Safety Nonaqueous Electrolytes and Interphases for Sodium‐Ion Batteries

Rapidly developed Na‐ion batteries are highly attractive for grid energy storage. Nevertheless, the safety issues of Na‐ion batteries are still a bottleneck for large‐scale applications. Similar to Li‐ion batteries (LIBs), the safety of Na‐ion batteries is considered to be tightly associated with the electrolyte and electrode/electrolyte interphase. Although the knowledge obtained from LIBs is helpful, designing safe electrolytes and obtaining stable interphases in Na‐ion batteries is still a huge challenge. Therefore, it is of significance to investigate the key factors and develop new strategies for the development of high‐safety Na‐ion batteries. This comprehensive review introduces the recent efforts from nonaqueous electrolytes and interphase aspects of Na‐ion batteries, proposes their design strategies and requirements for improving safety characteristics, and discusses the potential issues for practical applications. The insight to formulate safe electrolytes and design the stable interphase for Na‐ion batteries with high safety is intended to be provided herein.     

Dendrimer Based Binders Enable Stable Operation of Silicon Microparticle Anodes in Lithium-Ion Batteries

High-capacity anode materials (e.g., Si) are highly needed for high energy density battery systems, but they usually suffer from low initial coulombic efficiency (CE), short cycle life, and low-rate capability caused by large volume changes during the charge and discharge process. Here, a novel dendrimer-based binder for boosting the electrochemical performance of Si anodes is developed. The polyamidoamine (PMM) dendrimer not only can be used as binder, but also can be utilized as a crosslinker to construct 3D polyacrylic acid (PAA)-PMM composite binder for high-performance Si microparticles anodes. Benefiting from maximum interface interaction, strong average peeling force, and high elastic recovery rate of PAA-PMM composite, the Si electrode based on PAA-PMM achieves a high specific capacity of 3590 mAh g⁻¹ with an initial CE of 91.12%, long-term cycle stability with 69.80% retention over 200 cycles, and outstanding rate capability (1534.8 mAh g⁻¹ at 3000 mA g⁻¹). This work opens a new avenue to use dendrimer chemistry for the development of high-performance binders for high-capacity anode materials.