Surface/Interface Structure Degradation of Ni‐Rich Layered Oxide Cathodes toward Lithium‐Ion Batteries: Fundamental Mechanisms and Remedying Strategies

Abstract

Nickel‐rich layered transition‐metal oxides with high‐capacity and high‐power capabilities are established as the principal cathode candidates for next‐generation lithium‐ion batteries. However, several intractable issues such as the poor thermal stability and rapid capacity fade as well as the air‐sensitivity particularly for the Ni content over 80% have seriously restricted their broadly practical applications. The properties and nature of the stable surface/interface, where the Li+ shuttles back and forth between the cathode and electrolyte, play a significant role in their ultimate lithium‐storage performance and industrial processability. Thus, tremendous efforts are made to in‐depth understanding of the essential origins of surface/interface structure degradation and efficient surface modification methodologies are intensively explored. The purpose of the contribution is first to provide a comprehensive review of the up‐to‐date mechanisms proposed to rationally elucidate the surface/interface behaviors, and then, focus on recent developed strategies to optimize the surface/interface structure and chemistry including synthetic condition regulation, surface doping, surface coating, dual doping‐coating modification, and concentration‐gradient structure as well as electrolyte additives. Finally, the perspective on future research trends and feasible approaches toward advanced Ni‐rich cathodes with stable surface/interface is presented briefly.

Surface Modification Strategies for Improving the Cycling Performance of Ni‐Rich Cathode Materials

“…In CAMs, observed capacity losses originate from extrinsic factors, such as transition‐metal dissolution or decomposition of surface carbonates, as well as intrinsic loss mechanisms. The latter are based on changes in chemical bonding between the oxygen and the transition metal upon (de)lithiation, which destabilize the material via various degradation mechanisms, such as oxygen release at the surface and structural phase transitions, leading to mechanical fading , . Especially in Ni‐rich materials, the Ni 3 d and O 2 p states are hybridized, which has been probed directly by various X‐ray spectroscopic experiments sensitive to the oxidation state of the constituents , .…”

“…Consequently, the importance of controlling the cathode‐electrolyte interface via surface modification strategies will grow in the future. In this minireview, we summarize current approaches to surface modification to address the stability and longevity issues of the Ni‐rich NCM surface, in order to complement prior reviews on the topic of CAMs, and to categorize current investigations.…”

Fluorine-Doped LiNi0.8Mn0.1Co0.1O2 Cathode for High-Performance Lithium-Ion Batteries

“…Ni-based layered cathode materials, i.e., LiNi x Co y Mn z O 2 (x + y + z = 1) (NCM), have received attention recently as a promising alternative to LCO [9]. Specifically, NCM materials with high nickel contents (high-Ni cathode) have been used owing to their higher capacity [10]. However, serious problems with high-Ni cathodes have been observed during charging and discharging, such as destruction of the layered structure, cation mixing, oxygen evolution, and transition metal dissolution; these phenomena promote the irreversible consumption of Li + ions and thus degrade the LIB performance [11][12][13].…”

Cobalt‐based metal organic framework ( Co‐MOFs )/graphene oxide composites as high‐performance anode active materials for lithium‐ion batteries

“…Lithium‐ion batteries owing to high specific capacity and energy as well as long life are widely used in portable electronics and electric vehicles (EVs) 1‐7 . However, the increasing performance of EVs has promoted the continuous improvement of the electrochemical properties of lithium‐ion batteries.…”

“…Lithium-ion batteries owing to high specific capacity and energy as well as long life are widely used in portable electronics and electric vehicles (EVs). [1][2][3][4][5][6][7] However, the increasing performance of EVs has promoted the continuous improvement of the electrochemical properties of lithium-ion batteries. Normally, cathode materials generally determine the capacity and anode material determine the cycle life for lithium-ion batteries.…”