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Lithium‐metal batteries (LMBs) with high energy densities are highly desirable for energy storage, but generally suffer from dendrite growth and side reactions in liquid electrolytes; thus the need for solid electrolytes with high mechanical strength, ionic conductivity, and compatible interface arises. Herein, a thiol‐branched solid polymer electrolyte (SPE) is introduced featuring high Li+ conductivity (2.26 × 10−4 S cm−1 at room temperature) and good mechanical strength (9.4 MPa)/toughness (≈500%), thus unblocking the tradeoff between ionic conductivity and mechanical robustness in polymer electrolytes. The SPE (denoted as M‐S‐PEGDA) is fabricated by covalently cross‐linking metal–organic frameworks (MOFs), tetrakis (3‐mercaptopropionic acid) pentaerythritol (PETMP), and poly(ethylene glycol) diacrylate (PEGDA) via multiple CSC bonds. The SPE also exhibits a high electrochemical window (>5.4 V), low interfacial impedance (<550 Ω), and impressive Li+ transference number (tLi+ = 0.44). As a result, Li||Li symmetrical cells with the thiol‐branched SPE displayed a high stability in a >1300 h cycling test. Moreover, a Li|M‐S‐PEGDA|LiFePO4 full cell demonstrates discharge capacity of 143.7 mAh g−1 and maintains 85.6% after 500 cycles at 0.5 C, displaying one of the most outstanding performances for SPEs to date.

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Three-dimensional covalent organic frameworks (3D-COFs) are emerging as designable porous materials because of their unique structural characteristics and porous features. However, because of the lack of 3D organic building units and the less reversible covalent bonds, the topologies of 3D-COFs to date have been limited to dia, ctn, ffc, bor, rra, srs, pts, lon, stp, acs, tbo, bcu, and fjh. Here we report a 3D-COF with the ceq topology utilizing a D 3h -symmetric triangular prism vertex with a planar triangular linker. The as-synthesized COF displays a twofold-interpenetrated structure with a Brunauer–Emmett–Teller surface area of 1148.6 m2 g–1. Gas sorption measurements revealed that 3D-ceq-COF could efficiently absorb CO2, CH4, and H2 under a moderate surface area. This work provides new building units and approaches for structural and application exploration of 3D-COFs.

Layered Li‐rich cathode materials with high reversible energy densities are becoming prevalent. However, owing to the activation of low‐potential redox couples and the progressively irreversible structural transformation caused by the local adjustment of transition‐metal ions in the intra/interlayer driven by anionic redox, continuous capacity degradation, and voltage decay emerge, thus greatly reducing the energy density and increasing the difficulty of battery system management. Herein, layered Li‐rich cathode materials with higher intralayer configuration entropy have more local structural diversity and higher distortion energy, resulting in superior local structural adaptability with no drastic redox couple evolution, major local structural adjustment, or obvious layered‐to‐spinel phase transition. Consequently, the energy retention of the entropy‐stabilization‐strategy‐enhanced Li‐rich cathode materials is almost twice that of a typical Li‐rich cathode material (Li1.20Mn0.54Ni0.13Co0.13O2, T‐LRM) after 3 months of cyclic testing. Moreover, when cycled at 1 C, the voltage degradation per cycle is less than 0.02%, that is, it results in a voltage loss of only 0.8 mV per cycle, which is excellent performance. This study paves the way for the development of Li‐rich cathode materials with stabilized intralayer atomic arrangements and high local structural adaptability.

A solid-state electrolyte with a wide electrochemical window, high Li-ion conductivity, and anti-dendrite growth proper-ties are required for high-energy-density solid-state batteries. Here, we reported on a polyglycol oxide-based solid elec-trolyte...

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