Solid-state lithium batteries have become a research hotspot in the field of large-scale energy storage due to their excel-lent safety performance. The development of high-voltage positive electrode materials matched with lithium metal anode have advanced the energy density of solid-state lithium batteries close to or even exceeding that of lithium batteries based on a liquid electrolyte, which is expected to be commercialized in the future. However, in high voltage conditions (> 4.3 V), the decomposition of electrolyte components, structural degradation, and interface side reactions significantly reduce bat-tery performance and hinder its further development. This review summarizes the latest research progress of inorganic electrolytes, polymer electrolytes, and composite electrolytes in high-voltage solid-state lithium batteries. At the same time, the designs of high-voltage polymer gel electrolyte and high-voltage quasi solid-state electrolyte are introduced in detail. In addition, interface engineering is crucial for improving the overall performance of high-voltage solid-state batteries. Finally, we highlight the challenges faced by high-voltage solid-state lithium batteries and put forward our own views on future research directions. This review offers instructive insights into the advancement of high-voltage solid-state lithium batteries for large-scale energy storage applications.

Redox-active organic compounds have received much attention as high-capacity electrodes for rechargeable batteries. However, the high solubility in organic electrolytes during charge and discharge processes hinders the practical exploitation of organic compounds. This study presents a cobalt-based metal–organic coordination compound with bifunctional coordinated water (Co-MOC-H₂O) for sodium-ion storage. The coordinated water enhances interactions between sodium ions and nitrogen atoms in organic ligands through chelation, activating the inert sodium-ion storage sites (C=N). Moreover, the stable hydrogen bonded framework formed by the coordinated water molecules prevents the active organic compounds from dissolving into the electrolyte, thereby enhancing cycling stability. With the bifunctional coordinated water molecules, the Co-MOC-H₂O electrode delivers a high capacity of 403 mAh g⁻¹ at 0.2 A g⁻¹ over 600 cycles and exhibits a capacity retention of 77.9% at 2 A g⁻¹ after 1100 cycles. This work highlights the crucial role of the coordinated water molecules in constructing high capacity and long-life sodium-ion storage materials.

Pyrene-4,5,9,10-tetraone (PTO), with a high theoretical capacity of 408 mAh·g⁻¹, is a promising candidate for rechargeable aqueous zinc-ion batteries (RAZIBs), but its zincated products during discharge process suffer from high solubility in electrolytes. Herein, a β-ketoenamine-linked two-dimensional (2D) covalent organic framework (COF) based on a 2,7-diaminopyrene-4,5,9,10-tetraone (4KT-BD) monomer and a 2,4,6-trihydroxy-benzene-1,3,5-tricarbaldehyde (Tp) node (4KT-Tp-COF) is synthesized to address the above issue. The well-designed 4KT-Tp-COF displays low solubility in 3 M Zn(CF₃SO₃)₂ owing to the favorable π–π stacking as well as extended structure. Besides, the ingenious structural design of the active molecule and the long-range ordered nano-channels alter the intramolecular electron distribution, which facilitates the ionic diffusion. Consequently, the 4KT-Tp-COF cathode exhibits a stable capacity of 181 mAh·g⁻¹ at 0.2 A·g⁻¹, superior rate capability of 139 mAh·g⁻¹ at 20 A·g⁻¹, and a long lifetime of 1000 cycles without capacity loss at 30 A·g⁻¹. Even at a low temperature of −20 °C, the electrode also performs an ultralong cycling life of 9000 cycles with a capacity of 106 mAh·g⁻¹ at 5 A·g⁻¹. The comprehensive characterizations of ex-situ analyses together with the theoretical calculations validate that the groups of C=O can contribute highly accessible redox-active sites for Zn²⁺ storage. The ultra-stable 4KT-Tp-COF cathode provides important insights for designing robust organic electrodes for sustainable and large-scale electrochemical energy storage.