New Concepts in Electrolytes Li, Matthew; Wang, Chunsheng; Chen, Zhongwei ...
Chemical reviews,
07/2020, Letnik:
120, Številka:
14
Journal Article
Recenzirano
Odprti dostop
Over the past decades, Li-ion battery (LIB) has turned into one of the most important advances in the history of technology due to its extensive and in-depth impact on our life. Its omnipresence in ...all electric vehicles, consumer electronics and electric grids relies on the precisely tuned electrochemical dynamics and interactions among the electrolytes and the diversified anode and cathode chemistries therein. With consumers’ demand for battery performance ever increasing, more and more stringent requirements are being imposed upon the established equilibria among these LIB components, and it became clear that the state-of-the-art electrolyte systems could no longer sustain the desired technological trajectory. Driven by such gap, researchers started to explore more unconventional electrolyte systems. From superconcentrated solvent-in-salt electrolytes to solid-state electrolytes, the current research realm of novel electrolyte systems has grown to unprecedented levels. In this review, we will avoid discussions on current state-of-the-art electrolytes but instead focus exclusively on unconventional electrolyte systems that represent new concepts.
Silicon (Si) anodes are advantageous for application in lithium‐ion batteries in terms of their high theoretical capacity (4200 mAh g−1), appropriate operating voltage (<0.4 V vs Li/Li+), and ...earth‐abundancy. Nevertheless, a large volume change of Si particles emerges with cycling, triggering unceasing breakage/re‐formation of the solid‐electrolyte interphase (SEI) and thereby the fast capacity degradation in traditional carbonate‐based electrolytes. Herein, it is demonstrated that superior cyclability of Si anode is achievable using a nonflammable ether‐based electrolyte with fluoroethylene carbonate and lithium oxalyldifluoroborate dual additives. By forming a high‐modulus SEI rich in fluoride (F) and boron (B) species, a high initial Coulombic efficiency of 90.2% is attained in Si/Li cells, accompanied with a low capacity‐fading rate of only 0.0615% per cycle (discharge capacity of 2041.9 mAh g−1 after 200 cycles). Full cells pairing the unmodified Si anode with commercial LiFePO4 (≈13.92 mg cm−2) and LiNi0.5Mn0.3Co0.2O2 (≈17.9 mg cm−2) cathodes further show extended service life to 150 and 60 cycles, respectively, demonstrating the superior cathode‐compatibility realized with a thin and F, B‐rich cathode electrolyte interface. This work offers an easily scalable approach in developing high‐performance Si‐based batteries through Si/electrolyte interphase regulation.
A nonflammable and ether‐based electrolyte is formulated, enabling a highly stabilized Si anode and a LiNi0.5Mn0.3Co0.2O2 (NMC532) cathode. The high reversible capacity of the Si electrode is retained at 2041.9 mAh g−1 after 200 cycles, with a capacity fading rate of 0.0615% per cycle. A full cell coupling unmodified Si with a commercial NMC532 cathode demonstrates cycle life to 60 cycles.
Lithium‐ion batteries play a significant role in modern electronics and electric vehicles. However, current Li‐ion battery chemistries are unable to satisfy the increasingly heightened expectations ...regarding energy demand and reliability. To boost the overall energy density while ensuring the safety of Li batteries, researchers have focused on alternative battery materials, such as silicon, sulfur, and Li metal. These represent promising avenues, although numerous obstacles (e.g., Si cracking, polysulfide shuttling, Li dendrites, etc.) must be tackled before batteries based on these materials can enter mass production and penetrate the mainstream market. Polymers are a class of materials that are widely used in current battery systems; however, many novel polymer chemistries may offer better performance and reliability than the current ones, and even overcome the issues of the above‐mentioned new battery materials. In this review, selected polymeric materials for solving these issues are categorized into four parts: polymer electrolytes, polymer artificial solid‐electrolyte interphases, binders, and separators. Both the current progress and the characterization methods are included. Potential future directions of energy materials research are pointed out as well.
This review outlines the polymers used in lithium batteries and categorizes them into four sections: 1) solid polymer electrolytes, 2) polymer artificial solid electrolyte interphases, 3) binders, and 4) separators. Detailed examples, summary, and outlook are provided. Particularly, this review incorporates the experience from the battery industry and shows an organic combination between academia and industry.
So far, the practical application of Li metal batteries has been hindered by the undesirable formation of Li dendrites and low Coulombic efficiencies (CEs). Herein, 1,2‐diethoxyethane (DEE) is ...proposed as a new electrolytic solvent for lithium metal batteries (LMBs), and the performances of 1.0 m LiFSI in DEE are evaluated. Because of the low dielectric constant and dipole moment of DEE, the majority of the FSI− exists in associated states like contact ion pairs and aggregates, which is similar to the highly concentrated electrolytes. These associated complexes are involved in the reduction reaction on the Li metal anode, forming sound solid electrolyte interphase layers. Furthermore, free FSI− ions in DEE are observed to participate in the formation of cathode electrolyte interphase layers. These passivation layers not only suppress dendrite growth on the Li anode but also prevent unwanted side‐reactions on the LiFePO4 cathode. The average CE of the Li||Cu cells in LiFSI–DEE is observed to be 98.0%. Moreover, LiFSI–DEE also plays an important role in enhancing the cycling stability of the Li||LiFP cell with a capacity retention of 93.5% after 200 cycles. These results demonstrate the benefits of LiFSI–DEE, which creates new possibilities for high‐energy‐density rechargeable LMBs.
A consisting mixture of LiFSI and 1,2‐diethoxyethane (DEE)at 1.0 m is chosen as the novel electrolyte for lithium metal batteries. The LiFSI–DEE electrolyte is observed to be mostly dominated by CIPs and AGGs, which supports the simultaneous formation of sound SEI/CEI layers with inorganic conductive components. Consequently, cells with LiFSI–DEE not only exhibit high Coulombic efficiencies but also suppress Li dendrites.
Fluids and Electrolytes: A 2-in-1 Reference for Nurses offers both a serious reference book to read and a collection of logically organized bullet points for a quick review. The wide inner column of ...each page contains narrative text so nurses can, for instance, carefully read about the pathophysiology underlying an imbalance or the signs associated with the imbalance. The narrow outer column lists the corresponding summaries, better to rapidly review the key pathophysiologic events or key signs and symptoms. Full-color inserts enhance the content by bringing to life trademark ECG findings associated with two critical electrolytes, potassium and calcium, and their impact on myocardial function.
Garnet‐type solid‐state electrolytes (SSEs) are promising for the realization of next‐generation high‐energy‐density Li metal batteries. However, a critical issue associated with the garnet ...electrolytes is the poor physical contact between the Li anode and the garnet SSE and the resultant high interfacial resistance. Here, it is reported that the Li|garnet interface challenge can be addressed by using Li metal doped with 0.5 wt% Na (denoted as Li*) and melt‐casting the Li* onto the garnet SSE surface. A mechanistic study, using Li6.4La3Zr1.4Ta0.6O12 (LLZTO) as a model SSE, reveals that Li2CO3 resides within the grain boundaries of newly polished LLZTO pellet, which is difficult to remove and hinders the wetting process. The Li* melt can phase‐transfer the Li2CO3 from the LLZTO grain boundary to the Li*’s top surface, and therefore facilitates the wetting process. The obtained Li*|LLZTO demonstrates a low interfacial resistance, high rate capability, and long cycle life, and can find applications in future all‐solid‐state batteries (e.g., Li*|LLZTO|LiFePO4).
The lithium|garnet interface challenge is addressed by melt‐casting 0.5 wt% sodium‐doped lithium onto a garnet electrolyte surface. The doped lithium melt phase‐transfers the Li2CO3 from the grain boundaries of the garnet electrolyte pellet surface to the top of the doped lithium melt and therefore facilitates the wetting process.
Aqueous rechargeable batteries are becoming increasingly important to the development of renewable energy sources, because they promise to meet cost‐efficiency, energy and power demands for ...stationary applications. Over the past decade, efforts have been devoted to the improvement of electrode materials and their use in combination with highly concentrated aqueous electrolytes. Here the latest ground‐breaking advances in using such electrolytes to construct aqueous battery systems efficiently storing electrical energy, i.e., offering improved energy density, cyclability and safety, are highlighted. This Review aims to timely provide a summary of the strategies proposed so far to overcome the still existing hurdles limiting the present aqueous batteries technologies employing concentrated electrolytes. Emphasis is placed on aqueous batteries for lithium and post‐lithium chemistries, with potentially improved energy density, resulting from the unique advantages of concentrated electrolytes.
A matter of concentration: The latest ground‐breaking advances and strategies of using concentrated electrolyte for aqueous batteries, are discussed. Emphasis is placed on aqueous batteries for lithium and post‐lithium chemistries, with improved energy density, resulting from the unique properties of salt‐concentrated electrolytes.
Lithium (Li) metal is a promising candidate as the anode for high‐energy‐density solid‐state batteries. However, interface issues, including large interfacial resistance and the generation of Li ...dendrites, have always frustrated the attempt to commercialize solid‐state Li metal batteries (SSLBs). Here, it is reported that infusing garnet‐type solid electrolytes (GSEs) with the air‐stable electrolyte Li3PO4 (LPO) dramatically reduces the interfacial resistance to ≈1 Ω cm2 and achieves a high critical current density of 2.2 mA cm−2 under ambient conditions due to the enhanced interfacial stability to the Li metal anode. The coated and infused LPO electrolytes not only improve the mechanical strength and Li‐ion conductivity of the grain boundaries, but also form a stable Li‐ion conductive but electron‐insulating LPO‐derived solid‐electrolyte interphase between the Li metal and the GSE. Consequently, the growth of Li dendrites is eliminated and the direct reduction of the GSE by Li metal over a long cycle life is prevented. This interface engineering approach together with grain‐boundary modification on GSEs represents a promising strategy to revolutionize the anode–electrolyte interface chemistry for SSLBs and provides a new design strategy for other types of solid‐state batteries.
Li3PO4‐infused Li6.5La3Zr1.5Ta0.5O12 via atomic layer deposition with simple annealing is demonstrated to have excellent moisture stability and interfacial stability to a lithium anode by presenting negligible interfacial resistance (≈1 Ω cm2) and a record‐high critical current density of 2.2 mA cm−2 at ambient conditions. This new surface/subsurface engineering approach stabilizes the anode–electrolyte interface for solid‐state batteries.
Non-aqueous electrolyte liquids such as carbonate solvents have been widely employed in the commercial lithium-ion batteries and in the development of next-generation rechargeable batteries. The ...decomposition products of the organic electrolyte and additive molecules contribute to the formation of solid electrolyte interphases (SEIs) on the electrode surface, which have key impacts on battery's electrochemical performance. The rational engineering of electrolyte systems demands precise understanding of the electrochemical reaction pathways as well as the decomposition products of the electrolytes. Mass spectrometry (MS) is a well-established molecular analytical approach that can provide critical information for unambiguous structure assignment based on its mass-resolving power. In recent years, the application of MS for battery research has been expanding rapidly, providing valuable insights about the chemical species generated during battery operation and electrolyte evolution. This review aims to summarize the recent advances of MS technique-based analysis of electrolyte decomposition products as well as SEIs, and thus to demonstrate the high utility of MS methods for characterization of battery systems.
PDF
