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2024
ACL
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X.Gao , B.Li , G.Rousse , A.Morozov , M.Deschamps , L.Zhang , K.Kummer , A.Abakumov, J.-M.Tarascon, 'Achieving high-voltage stability in Li-rich Ni-rich oxides with local W/Ni(Li) superstructure', Adv. Energy Mat. 2402793 (2024)
Creating high-energy-density cathodes is crucial for building next-generation lithium-ion batteries. However, materials exploration along two main directions, namely Li-rich or Ni-rich oxides, has encountered bottlenecks. To get rid of the impasse, here we consolidated a “Li-rich Ni-rich” route by designing a new family of Li1+yNi(3-5y)/3W2y/3O2 oxides with high-voltage cycling stability up to 4.5 V and high capacities over 230 mAh g-1. We discovered that W6+ is largely incorporated into the LiNiO2 lattice, forming W/Ni(Li) inverse honeycomb-ordered nano-domains. These Li-rich domains enabled reversible anionic redox as clearly demonstrated by XAS, RIXS, TEM and NMR, being linked to the enhanced electrochemical performance. Moreover, the lattice incorporation of W6+ is proven to be the key to generate electrochemically active Li-rich domains independent of Li stoichiometry since similar local structure is found in W-substituted non-Li-rich oxides. It therefore implies the underestimated role of high-valence cations in tuning the structure and electrochemistry of Ni-rich oxides. These results highlight the necessity of a Li-rich composition in pursuing reversible high capacity, thus strengthening the promise of a “Li-rich Ni-rich” avenue for developing advanced cathodes.
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