As promising cathode materials, the lithium‐excess 3d‐transition‐metal layered oxides can deliver much higher capacities (>250 mAh g−1 at 0.1 C) than the current commercial layered oxide materials (≈180 mAh g−1 at 0.1 C) used in lithium ion batteries. Unfortunately, the original formation mechanism of these layered oxides during synthesis is not completely elucidated, that is, how is lithium and oxygen inserted into the matrix structure of the precursor during lithiation reaction? Here, a promising and practical method, a coprecipitation route followed by a microwave heating process, for controllable synthesis of cobalt‐free lithium‐excess layered compounds is reported. A series of the consistent results unambiguously confirms that oxygen atoms are successively incorporated into the precursor obtained by a coprecipitation process to maintain electroneutrality and to provide the coordination sites for inserted Li ions and transition metal cations via a high‐temperature lithiation. It is found that the electrochemical performances of the cathode materials are strongly related to the phase composition and preparation procedure. The monoclinic layered Li[Li0.2Ni0.2Mn0.6]O2 cathode materials with state‐of‐the‐art electrochemical performance and comparably high discharge capacities of 171 mAh g−1 at 10 C are obtained by microwave annealing at 750 °C for 2 h.

Reaction of antimony, selenium, and selenium(IV) chloride in the Lewis acidic ionic liquid [BMIM]Cl/AlCl(3) (BMIM: 1-n-butyl-3-methylimidazolium) at room temperature yielded air-sensitive black block-shaped crystals of [Sb(10)Se(10)][AlCl(4)](2). The triclinic unit cell (space group P1, a=947.85(2), b=957.79(2), c=1166.31(3) pm; α=103.622(1), β=110.318(1), γ=99.868(1)°; Z=1) contains the first mixed antimony/selenium polycation, [Sb(10)Se(10)](2+). The centrosymmetric polycyclic cation consists of two realgar-like [Sb(4)Se(4)] cages, which are connected through positively charged, three-bonded selenium atoms with a central [Sb(2)Se(2)] ring. Quantum chemical calculations predict semiconducting behavior of the compound and indicate primarily covalent bonding with varying ionic contribution within the [Sb(10)Se(10)](2+) polycation, while the interactions between the polycation and the [AlCl(4)](-) anions are predominantly ionic. The applicability of the Zintl concept to the chemical bonding in the heteronuclear polycation was evaluated by a thorough quantum chemical analysis.

For future Li-ion battery applications the search for both new design concepts and materials is necessary. The electrodes of the batteries are always in contact with electrolytes, which are responsible for the transport of Li ions during the charging and discharging process. A broad range of materials is considered for both electrolytes and electrodes so that very different chemical interactions between them can occur, while good cycling behavior can only be obtained for stable solid-electrolyte interfaces. X-ray photoelectron spectroscopy (XPS) was used to study the most relevant interactions between various electrode materials in contact with different electrolyte solutions. It is shown how XPS can provide useful information on reactivities and thus preselect suitable electrode/electrolyte combinations, prior to electrochemical performance tests.

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