Lithium‐ion batteries (LIBs) are promising candidates within the context of the development of novel battery concepts with high energy densities. Batteries with high operating potentials or high voltage (HV) LIBs (>4.2 V vs Li⁺/Li) can provide high energy densities and are therefore attractive in high‐performance LIBs. However, a variety of challenges (including solid electrolyte interface (SEI), lithium plating, etc.) and related safety issues (such as gas formation or thermal runaway effects) must be solved for the practical, widespread application of HV‐LIBs. Most of these challenges arise in the region between the electrodes: the electrolyte region. This review provides an overview of recent development and progress on the electrolyte region, including liquid electrolytes, ionic liquids, gel polymer electrolytes, separators, and solid electrolytes for HV‐LIBs applications. A focus on improving the safety of these systems, with some perspectives on their relative cost and environmental impact, is given. Overall, the new information is encouraging for the development of HV‐LIBs, and this review serves as a guide for potential strategies to improve their safety, allowing the development of HV‐LIBs, including solid‐state batteries, to be accelerated to practical relevance.

As the demand for lithium‐ion batteries (LIBs) continuously grows, the necessity to improve their efficiency/performance also grows. For this reason, optimization of the individual production steps is critical. Calendering is a crucial production step whereby electrode coatings are compacted to targeted densities. This process affects the porosity, adhesion, thickness, wettability, and charge transport properties of the electrodes, as well as the homogeneity of the coatings. Optimal calendered electrodes improve volumetric energy density, cyclic stability, and rate capability of the cells and also enhance the structural stability of the active material, which affects electrode safety and polarization. This article outlines the fundamental processes and mechanisms, as well as how modeling, simulation, and tomography can be used to optimize these processes. Additionally, the influence of calendering on a wide range of anode and cathode active materials is discussed. This review serves to give a deeper understanding into the calendering process‐structure‐performance relationships, and how they can be optimized to improve the performance of LIBs.

Current lithium (Li)‐metal anodes are not sustainable for the mass production of future energy storage devices because they are inherently unsafe, expensive, and environmentally unfriendly. The anode‐free concept, in which a current collector (CC) is directly used as the host to plate Li‐metal, by using only the Li content coming from the positive electrode, could unlock the development of highly energy‐dense and low‐cost rechargeable batteries. Unfortunately, dead Li‐metal forms during cycling, leading to a progressive and fast capacity loss. Therefore, the optimization of the CC/electrolyte interface and modifications of CC designs are key to producing highly efficient anode‐free batteries with liquid and solid‐state electrolytes. Lithiophilicity and electronic conductivity must be tuned to optimize the plating process of Li‐metal. This review summarizes the recent progress and key findings in the CC design (e.g. 3D structures) and its interaction with electrolytes.

The number of lithium‐ion batteries (LIBs) from hybrid and electric vehicles that are produced or discarded every year is growing exponentially, which may pose risks to supply lines of limited resources. Thus, recycling and regeneration of end‐of‐life LIBs (EoL‐LIBs) is becoming an urgent and critical task for a sustainable and environmentally friendly future. In this regard, much attention, especially in industry, is expended for developing recycling of cathode materials and the other valuable materials, but not much attention is dedicated to the recycling and reuse of graphite (Gr) from EoL‐LIBs. Herein, the current status of EoL‐LIB regeneration is summarized, with a focus on the recycling and purification of Gr, a state‐of‐the‐art anode material for most of the commercial LIBs. According to the recent advances regarding Gr recycling, three major regeneration processes of Gr are categorized, including i) washing Gr with different solvents, ii) thermal treatment process, and iii) hybrid (chemical and thermal) treatment processes. Depending on the source of the LIBs, and the method and quality of separation and purification, the recycled Gr can be reutilized as an active material for battery industries, including graphene production, as well as many other alternative applications, which are also addressed here.