Lithium metal (Li ) rechargeable batteries (LMBs), such as systems with a Li anode and intercalation and/or conversion type cathode, lithium-sulfur (Li-S), and lithium-oxygen (O )/air (Li-O /air) batteries, are becoming increasingly important for electrifying the modern transportation system, with the aim of sustainable mobility. Although some rechargeable LMBs (e.g. Li /LiFePO batteries from Bolloré Bluecar, Li-S batteries from OXIS Energy and Sion Power) are already commercially viable in niche applications, their large-scale deployment is hampered by a number of formidable challenges, including growth of lithium dendrites, electrolyte instability towards high voltage intercalation-type cathodes, the poor electronic and ionic conductivities of sulfur (S ) and O , as well as their corresponding reduction products (e.g. Li S and Li O), dissolution, and shuttling of polysulfide (PS) intermediates. This leads to a short lifecycle, low coulombic/energy efficiency, poor safety, and a high self-discharge rate. The use of electrolyte additives is considered one of the most economical and effective approaches for circumventing these problems. This Review gives an overview of the various functional additives that are being applied and aims to stimulate new avenues for the practical realization of these appealing devices.

Silicon has emerged as the next‐generation anode material for high‐capacity lithium‐ion batteries (LIBs). It is currently of scientific and practical interest to encounter increasingly growing demands for high energy/power density electrochemical energy‐storage devices for use in electric vehicles (xEVs), renewable energy sources, and smart grid/utility applications. Improvements to existing conventional LIBs are required to provide higher energy, longer cycle lives. This is attributed to its unparalleled theoretical capacity (4200 mAh g−1 for Li4.4Si), which is approximately 10 times higher than that of a state‐of‐the‐art graphitic anode (372 mAh g−1 for LiC6), with a suitable operating voltage, natural abundance, environmental benignity, nontoxicity, high safety, and so forth. However, despite the overwhelming beneficial features, the practical integration of LIBs containing a silicon anode beyond the commercial niche is hampered by unavoidable challenges, such as excessive volume changes during the (de‐)alloying process, inherently low electrical and ionic conductivities, an unstable solid–electrolyte interphase, and electrolyte drying out. Among various extenuating strategies, non‐electrode factors encompassing electrolyte additives and polymeric binders are regarded as the most economical, and effective approaches towards circumventing these disadvantages are in short supply. With the aim of providing an in‐depth insight into rapidly growing accounts of electrolyte additives and binders for use with silicon anode‐based LIBs, this Review assesses the current state of the art of research and thereby examines opportunities to open up new avenues for the practical realization of these silicon anode‐based LIBs.

Polymeric ionic liquids containing both ionic liquid-like moieties and polymer frameworks are promising alternative electrolytes/binders for Li-based rechargeable batteries.

Driven by the increasing plea for greener transportation and efficient integration of renewable energy sources, Ni-rich metal layered oxides, namely NMC, Li [Ni1−x−yCoyMnz] O2 (x + y ≤ 0.4), and NCA, Li [Ni1−x−yCoxAly] O2, cathode materials have garnered huge attention for the development of Next-Generation lithium-ion batteries (LIBs). The impetus behind such huge celebrity includes their higher capacity and cost effectiveness when compared to the-state-of-the-art LiCoO2 (LCO) and other low Ni content NMC versions. However, despite all the beneficial attributes, the large-scale deployment of Ni-rich NMC based LIBs poses a technical challenge due to less stability of the cathode/electrolyte interphase (CEI) and diverse degradation processes that are associated with electrolyte decomposition, transition metal cation dissolution, cation–mixing, oxygen release reaction etc. Here, the potential degradation routes, recent efforts and enabling strategies for mitigating the core challenges of Ni-rich NMC cathode materials are presented and assessed. In the end, the review shed light on the perspectives for the future research directions of Ni-rich cathode materials.

Layered lithium-rich nickel manganese cobalt oxide (LR-NMC) represents one of the most promising cathode materials for application in high energy density lithium-ion batteries. The extraordinary capacity delivered derives from a combination of both cationic and anionic redox processes. However, the latter ones lead to oxygen evolution which triggers structural degradation and electrode/electrolyte interface (EEI) instability that hinders the use of LR-NMC in practical application. In this work, we investigate the surface chemistry of LR-NMC and its evolution upon different conditions to give further insights into the processes occurring at the EEI. X-ray photoelectron spectroscopy studies reveal that once the organic component of the layer is formed, it remains stable independently on the higher cutoff voltage applied, while continuous growth of inorganics along with oxygen evolution occurs. The results performed on lithiated and delithiated LR-NMC surfaces indicate an instability of the EEI layer formed at high voltages, which undergoes a partial decomposition. Furthermore, the tris­(pentafluorophenyl)­borane electrolyte additive simultaneously prevents excess LiF formation and changes the chemical composition of the EEI layer. The latter is characterized by a higher amount of poly­(ethylene oxide) oligomer species and Li x PO y F z formation. In addition, the presence of boron-containing compounds in the EEI layer cannot be excluded, which may be also responsible of the increased thickness of the EEI layer. Finally, fast kinetics at elevated temperatures exacerbate the salt decomposition which results in the formation of an EEI which is thicker and richer in LiF.

Since the oil crisis in the 1970s, the importance of rechargeable batteries has been noted by academia and industrial sectors. This becomes more prominent with increasing demand in e-mobility and...

Silicon (Si) has gained huge attention as an anode material for next-generation high-capacity lithium-ion batteries (LIBs). However, despite its overwhelming beneficial features, its large-scale commercialization is hampered due to unavoidable challenges such as colossal volume change during (de)­alloying, inherent low electronic and ionic conductivities, low Coulombic efficiency, unstable/dynamic solid electrolyte interphase (SEI), electrolyte drying and so forth. Among other strategies, the use of a fraction dose of chemical additives is hailed as the most effective, economic and scalable approach to realize Si-anode-based LIBs. Functional additives can modify the nature and chemical composition of the SEI, which in turn dictates the obtainable capacity, rate capability, Coulombic/energy efficiency, safety, and so forth of the battery system. Thus, we report a systematic and comparative investigation of various electrolyte additives, namely tetraethoxysilane (TEOS), (2-cyanoethyl)­triethoxysilane (TEOSCN), vinylene carbonate (VC), fluoroethylene carbonate (FEC), and a blend of TEOSCN, VC, and FEC (i.e., VC/FEC/TEOSCN) using electrochemical analysis, X-ray photoelectron spectroscopy, density functional theory calculation, and differential scanning calorimetry. The ternary mixture (FEC/VC/TEOSCN) results in a thinner SEI layer consisting of high shear modulus SEI-building species (mainly LiF). It also provides much improved thermal stability amid all tested additives, showing its potentiality to enable high capacity and safer Si-based anode LIBs. Thus, nitrile-functionalized silanes are highly promising electrolyte additives to boost the electrochemical performance and safety-induced risks of Si-based anode LIBs, emanating from the formation of a robust SEI layer.

The dosage of (2-cyanoethyl)triethoxysilane (TEOSCN) is investigated as the electrode/electrolyte interface modulating electrolyte additive to improve the performance of LiN0.6Mn0.2Co0.2O2/silicon–graphite batteries at a high temperature (45 °C).