Cong Lin

Li-rich layered oxides (LLOs) are promising high-energy cathodes but suffer from irreversible oxygen redox and structural degradation associated with Li2MnO3 domains. Recently, disorder engineering has emerged as an effective strategy to regulate the local coordination environment and stabilize the oxygen redox of LLOs. Herein, we confirm the existence of intrinsic intralayer Li/Mn disorder within the Li2MnO3 domains, which can be classified into local Li-excess and TM-excess configurations derived from the initial Li-rich framework. Furthermore, DFT calculations suggest complementary local roles for the different disordered configurations: Li-excess domains promote oxygen redox activity, whereas TM-excess domains reinforce TM–O bonding and stabilize the framework against irreversible degradation. Consequently, M-LLO containing the coupled disordered configurations promotes more reversible anionic redox, suppresses irreversible oxygen release and transition-metal migration, and thereby delivers improved electrochemical stability. This work provides new insights into the role of intrinsic disorder regulation in Li-rich layered cathodes.

Structural ordering regulation via synthesis temperature dictates the structure, anionic redox, and electrochemistry of manganese-rich layered cathodes, while an optimized structural ordering degree enhances anionic redox and structural stability.

Structural dynamics in metal–organic frameworks (MOFs) typically rely on elaborate, flexible organic linkers. Here, we challenge this paradigm by demonstrating a rare, reversible 5‐phase‐transition cycle in a minimalist cobalt formate MOF system. Central to this evolution is the conceptual reframing of the amorphous state ( Co‐Amor ); rather than representing a structural dead‐end, Co‐Amor functions as a programmable, high‐energy reactive hub that lowers reorganization barriers. We show that specific guest molecules selectively direct the reconstruction of this amorphous matrix into distinct crystalline architectures, including chiral ( Co‐Hex ), perovskite‐like ( Co‐Trig ), diamondoid ( Co‐Mono1 ), and hydrated ( Co‐Mono2 ) frameworks, effectively ‘reprogramming’ the material's underlying lattice physics. The generality of the guest‐molecule selectivity is verified by Co‐Hex and Co‐Trig , which have different crystalline structures but share the same phase‐transition behavior, thereby further highlighting the adaptability and importance of this system. Most notably, we uncover a rare gas‐solid reconstruction where CO ₂ acts as a morphogenic trigger, inducing a gradual amorphous‐to‐crystal transition to the rigid Co‐Mono1 phase. This chemoselectivity originates from a specific C–H···O hydrogen‐bond complementarity between the formate channel walls and CO ₂ . This work highlights the untapped potential of amorphous intermediates in directing structural reconfigurations, offering a blueprint for designing highly adaptive materials from the simplest molecular building blocks.

Although the anionic activity in layered oxide positive electrodes is partially understood, the mechanism by which it induces internal crack propagation under high-voltage conditions remains unclear, severely limiting stable cycle life and available capacity. In this study, the mechanism underlying internal crack propagation is elucidated in LiCoO₂ under harsh float-charge conditions at 60 °C and a potential of 4.6 V vs. Li⁺/Li. We reveal that sequential phase transitions from O3 to O1 and then to a cation-mixed phase during deep Li⁺ extraction generate significant lattice-mismatch stresses that initiate internal cracks. Crucially, the accompanying anionic activity drives the migration of the oxidized lattice Oⁿ⁻ (0 < n < 2) towards these cracks, where it even accumulates as molecular O₂ that can be released upon crack propagation to the surface. It is identified that the sustained O1tocation-mixed phase transition and the bulk lattice Oⁿ⁻ migration synergistically drive the interior crack propagation, ultimately leading to LiCoO₂ disintegration and electrochemical degradation. This work not only deepens our understanding of the anionic activity in layered positive electrodes but also provides mechanistic insights for the future design of stable LiCoO₂ positive electrodes.

We demonstrate the sorption chemistry can be regulated by extra-framework counter-cations in metal–organic frameworks.

Rapid capacity decay caused by lattice oxygen (lattice-O) loss under high-voltage operation remains a critical challenge for layered LiCoO₂ (LCO) cathodes. Recently, various surface modification strategies have been explored to suppress lattice-O loss, yet the underlying mechanisms remain controversial. Herein, we identify slab-gliding-induced surface nanosteps on LCO and elucidate their role in driving lattice-O loss. These nanosteps (10-20 nm per step) are induced by local Co-O slab gliding during phase transitions upon deep delithiation, thereby exposing numerous active lattice O^n- (0 < n < 2) sites on the (003) and (104) planes, where oxygen vacancies (O_Vs) can form with significantly reduced formation energies. Consequently, this accelerates lattice-O loss and promotes the formation of a surface Li⁺-blocking layer, ultimately causing a rapid capacity decay. We further demonstrate that even if a rock-salt (RS) phase forms electrochemically in situ (e-RS) on the LCO surface, it fails to suppress the lattice-O loss due to the emergence of surface nanosteps. In contrast, a prefabricated RS layer (p-RS) with enhanced mechanical robustness effectively inhibits the formation of such nanosteps, thereby intrinsically suppressing lattice-O loss during cycling. This work identifies slab-gliding-induced surface nanosteps as a key structural trigger for lattice-O loss and demonstrates that prefabricated RS coatings offer an effective route to stabilize high-voltage LCO cathodes.

Stable extra-large-pore zeolites are highly desirable for catalysis and molecular separation, but most remain microporous, limiting their effectiveness for bulky substrates. Among the few extra-large-pore zeolites that exhibit mesoporosity, the pores typically form as elongated, noncircular pore apertures. We report that NJU120-6, a stable silicate zeolite with an intrinsic cylindrical mesoporous system, has the currently largest 36-ring windows with a free diameter of 25.71 angstroms by 19.12 angstroms. NJU120-6 exhibits the lowest framework density of 9.39 silicon atoms per cubic nanometer and a pore volume of 0.66 cubic centimeters per gram. It remains stable up to 1173 kelvin and can incorporate aluminum and titanium, enabling superior performance in catalytic cracking and in liquid-phase alkene oxidation of bulky molecules, respectively.

Stable zeolites with extra-large pores and nano dimensions that are capable of processing large molecules are in high demand but have been difficult to produce. Their complex structures and nanoscale crystal sizes present challenges for analysis using conventional x-ray diffraction techniques, leading to inefficiencies in material development. We report NJU120-1 and NJU120-2, two robust and fully connected aluminosilicate nano zeolites featuring interconnected channel systems with extra-large 22-ring pores. NJU120-1 is a nanosheet with only about 8-nanometer thickness, corresponding to 1.5 unit cells, and NJU120-2 is a nanorod with 50 by 250 nanometer dimensions. Their synthesis optimization was greatly accelerated through rapid structure determination with MicroED, revealing their multidimensional pore structures. Their very large largest-free-sphere diameters of approximately 1.2 nanometers coupled with nano morphologies enabled catalytic cracking of large molecules.