Rechargeable Li-based battery technologies utilising silicon, silicon-based, and Si-derivative anodes coupled with high-capacity/high-voltage insertion-type cathodes have reaped significant interest from both academic and industrial sectors. This stems from their practically achievable energy density, offering a new avenue towards the mass-market adoption of electric vehicles and renewable energy sources. Nevertheless, such high-energy systems are limited by their complex chemistry and intrinsic drawbacks. From this perspective, we present the progress, current status, prevailing challenges and mitigating strategies of Li-based battery systems comprising silicon-containing anodes and insertion-type cathodes. This is accompanied by an assessment of their potential to meet the targets for evolving volume- and weight-sensitive applications such as electro-mobility.

those being implemented in solving global challenges remain accompanied by an energy reliance on non-renewable fossil fuels. The accelerated depletion of stocks of these energy sources, together with their associated pollution drives the need to expedite establishment of robust renewable alternatives. Often termed "renewables" or "clean energy," these power sources have a perennial temporalavailability and thus have greater need for energy repositories than non-renewables. Hence, prompt optimization of energy storage-delivery devices is crucial to the sustainable development, scaling, commercial delivery, and global establishment of reliable clean energy. [1,2] Batteries and electrochemical devices have most often filled the majority of power-storage and are ubiquitous as energy mediation devices, capable of harnessing large amount of energy for various applications including the aerospace, travel and transport, and electronics industries, among others. [3][4][5][6] The future of batteries lies with devices produced from ever-more sustainable components that can offer improved safety, transportability, extended battery life, have short recharge times as well as low production costs and Interfacial dynamics within chemical systems such as electron and ion transport processes have relevance in the rational optimization of electrochemical energy storage materials and devices. Evolving the understanding of fundamental electrochemistry at interfaces would also help in the understanding of relevant phenomena in biological, microbial, pharmaceutical, electronic, and photonic systems. In lithium-ion batteries, the electrochemical instability of the electrolyte and its ensuing reactive decomposition proceeds at the anode surface within the Helmholtz double layer resulting in a buildup of the reductive products, forming the solid electrolyte interphase (SEI). This review summarizes relevant aspects of the SEI including formation, composition, dynamic structure, and reaction mechanisms, focusing primarily on the graphite anode with insights into the lithium metal anode. Furthermore, the influence of the electrolyte and electrode materials on SEI structure and properties is discussed. An update is also presented on state-of-theart approaches to quantitatively characterize the structure and changing properties of the SEI. Lastly, a framework evaluating the standing problems and future research directions including feasible computational, machine learning, and experimental approaches are outlined.

Absorption and capture of CO 2 directly from sources represents one of the major tools to reduce its emission in the troposphere. One of the possibilities is to incorporate CO 2 inside a liquid exploiting its propensity to react with amino groups to yield carbamic acid or carbamates. A particular class of ionic liquids, based on amino acids, appear to represent a possible efficient medium for CO 2 capture because, at difference with current industrial setups, they have the appeal of a biocompat-ible and environmentally benign solution. We have investigated, by means of highly accurate computations, the feasibility of the reaction that incorporates CO 2 in an amino acid anion with a protic side chain and ultimately transforms it into a carbamate derivative. Through an extensive exploration of the possible reaction mechanisms, we have found that different prototypes of amino acid anions present barrierless reaction mechanisms toward CO 2 absorption.

The local structure of a series of homologous protic ionic liquids (PILs) is investigated using ab initio computations and ab initio-based molecular dynamics. The purpose of this work is to show that in PILs the network of hydrogen bonds may promote like-charge clustering between anionic species. We correlate the theoretical evidence of this possibility with viscosity experimental data. The homologous series of liquids is obtained by coupling choline with amino acid anions and varying the side chain. We find that the frictional properties of the liquids are clearly connected to the ability of the side chain to establish additional hydrogen bonds (other than the trivial cation–anion interaction). We also show that the large variation of bulk properties along the series of compounds can be explained by assuming that one of the sources of friction in the bulk liquid is the like-charge interaction between anions.

Lithium metal anodes are ideal for realizing high-energy-density batteries owing to their advantages, namely high capacity and low reduction potentials. However, the utilization of lithium anodes is restricted by the detrimental lithium dendrite formation, repeated formation and fracturing of the solid electrolyte interphase (SEI), and large volume expansion, resulting in severe “dead lithium” and subsequent short circuiting. Currently, the researches are principally focused on inhibition of dendrite formation toward extending and maintaining battery lifespans. Herein, we summarize the strategies employed in interfacial engineering and current-collector host designs as well as the emerging electrochemical catalytic methods for evolving-accelerating-ameliorating lithium ion/atom diffusion processes. First, strategies based on the fabrication of robust SEIs are reviewed from the aspects of compositional constituents including inorganic, organic, and hybrid SEI layers derived from electrolyte additives or artificial pretreatments. Second, the summary and discussion are presented for metallic and carbon-based three-dimensional current collectors serving as lithium hosts, including their functionality in decreasing local deposition current density and the effect of introducing lithiophilic sites. Third, we assess the recent advances in exploring alloy compounds and atomic metal catalysts to accelerate the lateral lithium ion/atom diffusion kinetics to average the spatial lithium distribution for smooth plating. Finally, the opportunities and challenges of metallic lithium anodes are presented, providing insights into the modulation of diffusion kinetics toward achieving dendrite-free lithium metal batteries.

Non-flammable ionic liquid electrolytes (ILEs) are well-known candidates for safer and long-lifespan lithium metal batteries (LMBs). However, the high viscosity and insufficient Li + transport limit their practical application. Recently, non-solvating and low-viscosity co-solvents diluting ILEs without affecting the local Li + solvation structure are employed to solve these problems. The diluted electrolytes, i.e., locally concentrated ionic liquid electrolytes (LCILEs), exhibiting lower viscosity, faster Li + transport, and enhanced compatibility toward lithium metal anodes, are feasible options for the next-generation high-energy-density LMBs. Herein, the progress of the recently developed LCILEs are summarised, including their physicochemical properties, solution structures, and applications in LMBs with a variety of high-energy cathode materials. Lastly, a perspective on the future research directions of LCILEs to further understanding and achieve improved cell performances is outlined.

Batteries & Supercaps www.batteries-supercaps.org Review doi.org/10.1002/batt.202200097 Lithium-sulfur (LiÀ S) batteries are recognized as one of the most promising technologies with the potential to become the next-generation batteries. However, to ensure LiÀ S batteries reach commercialization, complex challenges remain, among which the tailoring of an appropriate electrolyte is the most important. This review discusses the role of electrolytes in LiÀ S batteries, focusing on the main issues and solutions for the shuttle mechanism of polysulfides and the instability of the interface with lithium metal. Herein, we present a background on LiÀ S chemistry followed by the state-of-the-art electrolytes highlighting the different strategies undertaken with liquid and solid electrolytes.

An analysis of the complex proton transfer processes in certain protic ionic liquids, based on amino acid anions, has been carried out through ab initio molecular dynamics in the view of finding naturally conductive and pure mediums. The systems analyzed here might serve as chemical prototypes for pure and dry ionic liquids where mobile protons can act as fast charge carriers. We have exploited the natural tendency of these liquids to form a complex network of hydrogen bonds. The presence of such a network allows the naturally repulsive interaction between like charge ions to be weakened to the point that a proton migration process inside the anionic component of the fluid becomes possible. We have also seen that the extent of these proton migrations is sizable for carboxylic based amino acid anions, while it is very limited for sulfur containing ones.