One‐Step Calcination Synthesis of Bulk‐Doped Surface‐Modified Ni‐Rich Cathodes with Superlattice for Long‐Cycling Li‐Ion Batteries

Abstract

Nickel‐rich (Ni≥90 %) layered cathodes are critical materials for achieving higher‐energy‐density and lower‐cost next‐generation Li‐ion batteries (LIBs). However, their bulk and interface structural instabilities significantly impair their electrochemical performance, thus hindering their widespread adoption in commercial LIBs. Exploiting Ti and Mo diffusion chemistry, we report one‐step calcination to synthesize bulk‐to‐surface modified LiNi0.9Co0.09Mo0.01O2 (NCMo90) featuring a 5 nm Li2TiO3 coating on the surface, a Mo‐rich Li+/Ni2+ superlattice at the sub‐surface, and Ti‐doping in the bulk. Such a multi‐functional structure effectively maintains its structural integrity upon cycling. As a result, such NCMo90 exhibits a high initial capacity of 221 mAh g−1 at 0.1 C, excellent rate performance (184 mAh g−1 at 5 C), and high capacity retention of 94.0 % after 500 cycles. This work opens a new avenue to developing industry‐applicable Ni‐rich cathodes for next‐generation LIBs.

Maintaining Interfacial Transports for Sulfide-Based All-Solid-State Batteries Operating at Low External Pressure

“…The lattice fringes of the coating layer (Figure B II ) with a d -spacing of 0.225 nm coincide well with the (2̅02) planes of the Li 2 ZrO 3 phase ( C2/c space group) . The subsurface nanolayer is attributed to the Al/Zr-rich rocksalt phase (superlattice) with a d -spacing of 0.238 nm (Figure B III ), stabilizing the delithiated layered structure . High-resolution energy-dispersive spectroscopy (EDS) mappings show the diffusion depth of Al and Zr elements, in which the Al element diffused into the bulk of SC811, and the Zr element enriched in the surface (Figure C).…”

“…39 The subsurface nanolayer is attributed to the Al/Zr-rich rocksalt phase (superlattice) with a d-spacing of 0.238 nm (Figure 2B III ), stabilizing the delithiated layered structure. 40 High-resolution energy-dispersive spectroscopy (EDS) mappings show the diffusion depth of Al and Zr elements, in which the Al element diffused into the bulk of SC811, and the Zr element enriched in the surface (Figure 2C). The quantitative distribution information of Al and Zr elements based on EDS analysis further reveals that Zr enriches in the (sub)surface region (≤80 nm), and Al enriches in the bulk phase region (Figures S7, S8), which is consistent with the results of Ar + sputtering-assisted X-ray photoelectron spectroscopy (XPS) (Figure S9).…”

“…In addition, a small amount of Zr doped into the subsurface lattice to form the Zr-rich rocksalt phase, which enhanced the structural stability of the surface lattice upon lithiation/ delithiation. 40 As a result, the Al/Zr element doping engineering has given rise to the surface-to-bulk pillar effect of the Nirich cathode. Meanwhile, the surface rocksalt superlattice and bulk Al doping can mitigate the volumetric shrinkage and suppress the irreversible H2−H3 phase transition at the highly delithiated state, thus improving the abrupt volumetric strain at high SOC.…”

“…The Li 2 ZrO 3 phase coating layer exhibited low interfacial reaction energy and suppressed the interfacial side reaction between CAM/SSE (Figure S15). In addition, a small amount of Zr doped into the subsurface lattice to form the Zr-rich rocksalt phase, which enhanced the structural stability of the surface lattice upon lithiation/delithiation . As a result, the Al/Zr element doping engineering has given rise to the surface-to-bulk pillar effect of the Ni-rich cathode.…”

In Situ Doping Polyanions Enables Concentration-Gradient Ni-Rich Cathodes for Long-Life Lithium-Ion Batteries

“…Serving as the pivotal component that influences the performance and cost of lithium-ion batteries, nickel-rich cathode materials are widely used for their superior reversible specific capacity and acceptable cost. − Nevertheless, the nickel-rich cathode is still confronted with the problem of capacity degradation and poor thermal stability caused by interfacial instability in practical applications. − Recent studies have shown that the development of a concentration-gradient cathode serves as a potent method for optimizing the capacity and cycle stability of a high-nickel cathode. − In the secondary particles featuring a gradient structure, the nickel concentration gradually decreases from the inner core to the outer surface, while the manganese content increases steadily . The Ni-rich fraction in the inner core ensures a high specific capacity, while the Mn-rich fraction in the outer layer reduces the surface reactivity and exhibits high thermal stability .…”