Being successfully introduced into the market only 30 years ago, lithium‐ion batteries have become state‐of‐the‐art power sources for portable electronic devices and the most promising candidate for energy storage in stationary or electric vehicle applications. This widespread use in a multitude of industrial and private applications leads to the need for recycling and reutilization of their constituent components. Improving the “recycling technology” of lithium ion batteries is a continuous effort and recycling is far from maturity today. The complexity of lithium ion batteries with varying active and inactive material chemistries interferes with the desire to establish one robust recycling procedure for all kinds of lithium ion batteries. Therefore, the current state of the art needs to be analyzed, improved, and adapted for the coming cell chemistries and components. This paper provides an overview of regulations and new battery directive demands. It covers current practices in material collection, sorting, transportation, handling, and recycling. Future generations of batteries will further increase the diversity of cell chemistry and components. Therefore, this paper presents predictions related to the challenges of future battery recycling with regard to battery materials and chemical composition, and discusses future approaches to battery recycling.

Recently, dual-ion cells based on the anion intercalation into a graphite positive electrode have been proposed as electrochemical energy storage devices. For this technology, in particular electrolytes which display a high stability vs. oxidation are required due to the very high operation potentials of the cathode, which may exceed 5 V vs. Li/Li⁺. In this work, we present highly promising results for the use of graphite as both the anode and cathode material in a so-called “dual-graphite” or “dual-carbon” cell. A major goal for this system is to find suitable electrolyte mixtures which exhibit not only a high oxidative stability at the cathode but also form a stable solid electrolyte interphase (SEI) at the graphite anode. As an electrolyte system, the ionic liquid-based electrolyte mixture Pyr₁₄TFSI-LiTFSI is used in combination with the SEI-forming additive ethylene sulfite (ES) which allows stable and highly reversible Li⁺ ion and TFSI⁻ anion intercalation/de-intercalation into/from the graphite anode and cathode, respectively. By addition of ES, also the discharge capacity for the anion intercalation can be remarkably increased from 50 mA h g⁻¹ to 97 mA h g⁻¹. X-ray diffraction studies of the anion intercalation into graphite are conducted in order to understand the influence of the electrolyte additive on the graphite structure and on the cell performance.

The 1st cycle Coulombic efficiency (CE) of LiNi_1/3Co_1/3Mn_1/3O₂ (NCM) at 4.6 V vs. Li/Li⁺ has been extensively investigated in NCM/Li half cells. It could be proven that the major part of the observed overall specific capacity loss (in total 36.3 mA h g⁻¹) is reversible and induced by kinetic limitations, namely an impeded lithiation reaction during discharge. A measure facilitating the lithiation reaction, i.e. a constant potential (CP) step at the discharge cut-off potential, results in an increase in specific discharge capacity of 22.1 mA h g⁻¹. This capacity increase during the CP step could be proven as a relithiation process by Li⁺ content determination in NCM via an ICP-OES measurement. In addition, a specific capacity loss of approx. 4.2 mA h g⁻¹ could be determined as an intrinsic reaction to the NCM cathode material at room temperature (RT). In total, less than 10.0 mA h g⁻¹ (=28% of the overall capacity loss) can be attributed to irreversible reactions, mainly to irreversible structural changes of NCM. Thus, the impact of parasitic reactions, such as oxidative electrolyte decomposition, on the irreversible capacity is negligible and could also be proven by on-line MS. As a consequence, the determination of the amount of extracted Li⁺ (“Li⁺ extraction ratio”) so far has been incorrect and must be calculated by the charge capacity (=delithiation amount) divided by the theoretical capacity. In a NCM/graphite full cell the relithiation amount during the constant voltage (CV) step is smaller than in the half cell, due to irreversible Li⁺ loss at graphite.