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Wadsley‐Roth niobium oxide phases have attracted extensive research interest recently as promising battery anodes. We have synthesized the niobium‐molybdenum oxide shear phase (Nb, Mo)13O33 with superior electrochemical Li‐ion storage performance, including an ultralong cycling lifespan of at least 15000 cycles. During electrochemical cycling, a reversible single‐phase solid‐solution reaction with lithiated intermediate solid solutions is demonstrated using in situ X‐ray diffraction, with the valence and short‐range structural changes of the electrode probed by in situ Nb and Mo K‐edge X‐ray absorption spectroscopy. This work reveals that the superior stability of niobium molybdenum oxides is underpinned by changes in octahedral distortion during electrochemical reactions, and we report an in‐depth understanding of how this stabilizes the oxide structure during cycling with implications for future long‐life battery material design. [ABSTRACT FROM AUTHOR]

Oxides composed of an oxygen framework and interstitial cations are promising cathode materials for lithium‐ion batteries. However, the instability of the oxygen framework under harsh operating conditions results in fast battery capacity decay, due to the weak orbital interactions between cations and oxygen (mainly 3d–2p interaction). Here, a robust and endurable oxygen framework is created by introducing strong 4s–2p orbital hybridization into the structure using LiNi0.5Mn1.5O4 oxide as an example. The modified oxide delivers extraordinarily stable battery performance, achieving 71.4 % capacity retention after 2000 cycles at 1 C. This work shows that an orbital‐level understanding can be leveraged to engineer high structural stability of the anion oxygen framework of oxides. Moreover, the similarity of the oxygen lattice between oxide electrodes makes this approach extendable to other electrodes, with orbital‐focused engineering a new avenue for the fundamental modification of battery materials. [ABSTRACT FROM AUTHOR]

Spinel LiNi0.5Mn1.5O4 (LNMO) is a promising cathode candidate for the next‐generation high energy‐density lithium‐ion batteries (LIBs). Unfortunately, the application of LNMO is hindered by its poor cycle stability. Now, site‐selectively doped LNMO electrode is prepared with exceptional durability. In this work, Mg is selectively doped onto both tetrahedral (8a) and octahedral (16c) sites in the Fd3‾ m structure. This site‐selective doping not only suppresses unfavorable two‐phase reactions and stabilizes the LNMO structure against structural deformation, but also mitigates the dissolution of Mn during cycling. Mg‐doped LNMOs exhibit extraordinarily stable electrochemical performance in both half‐cells and prototype full‐batteries with novel TiNb2O7 counter‐electrodes. This work pioneers an atomic‐doping engineering strategy for electrode materials that could be extended to other energy materials to create high‐performance devices. [ABSTRACT FROM AUTHOR]

Metal-organic framework materials (MOFs) have recently been shown in some cases to exhibit strong negative thermal expansion (NTE) behavior, while framework interpenetration has been found to reduce NTE in many materials. Using powder and single-crystal diffraction methods we investigate the thermal expansion behavior of interpenetrated Cu3(btb)2 (MOF-14) and find that it exhibits an anomalously large NTE effect. Temperature-dependent structural analysis shows that, contrary to other interpenetrated materials, in MOF-14 the large positive thermal expansion of weak interactions that hold the interpenetrating networks together results in a low-energy contractive distortion of the overall framework structure, demonstrating a new mechanism for NTE. [ABSTRACT FROM AUTHOR]