Alleviating Surface Degradation of Nickel-Rich Layered Oxide Cathode Material by Encapsulating with Nanoscale Li-Ions/Electrons Superionic Conductors Hybrid Membrane for Advanced Li-Ion Batteries

Abstract

Nickel-rich layered oxide cathode materials for advanced lithium-ion batteries have received much attention recently because of their high specific capacities and significant reduction of cost. However, these cathodes are facing a fundamental challenge of loss in performance as a result of surface lithium residue, side reactions with the electrolyte and structure rearrangement upon long-term cycling. Herein, by capturing the lithium residue on the surface of LiNiCoMnO (NCM) cathode material as Li source, we propose a hybrid coating strategy incorporating lithium ions conductor LiAlO with superconductor LiTiO to overcome those obstinate issues. By taking full advantage of this unique hybrid nanomembrane coating architecture, both the lithium ion diffusion ability and electronic conductivity of LiNiCoMnO cathode material are improved, resulting in remarkably enhanced electrochemical performances during high voltage operation, including good cycle performance, high reversible capacity, and excellent rate capability. A high initial discharge capacity of 227 mAh g at 4.4 V cutoff voltage with Coulombic efficiency of 87.3%, and reversible capacity of 200 mAh g with 98% capacity retention after 100 cycles at a current density of 0.5 C can be attained. The improved electrochemical performance can be attributed to the synergetic contribution from the removal of lithium residues and the unique hybrid nanomembrane coating architecture. Most importantly, this surface modification technique could save some cost, simplify the technical procedure, and show great potential to optimize battery performance, apply in a large scale and extend to all nickel-rich cathode material.

Degradation Mechanisms and Mitigation Strategies of Nickel-Rich NMC-Based Lithium-Ion Batteries

“…Moreover, the introduction of acids or metal oxides can allow for excessive Li on the surface of cathodic particles to transform into Li x M y O z coatings at certain temperatures [196]. For example, researchers suggested that the use of excessive surface Li on NMC811 to form a protective layer consisting of Li + -conductive Li x AlO 2 and superconductive Li x Ti 2 O 4 [197] was a cost-saving and efficient method to resolve the issue of excessive Li and improve conductivity.…”

Realizing Three‐Electron Redox Reactions in NASICON‐Structured Na3MnTi(PO4)3 for Sodium‐Ion Batteries

“…Obviously, the NMTP/C-650 outperforms the NMTP/C-600 and NMTP/ C-700 in terms of specific discharge capacity and rate capability (Figure 3d; Figures S9 and S10, Supporting Information). The equivalent electrical circuit for fitting the impedance data is shown in the inset of Figure S11 in the Supporting Information [27,[33][34][35] and the fitting results are summarized in Table S4 in the Supporting Information. Under the same conditions, the NMTP/C-600 and NMTP/C-700 exhibit much lower discharge capacities and capacity retentions.…”

Rational Architecture Design Enables Superior Na Storage in Greener NASICON‐Na4MnV(PO4)3 Cathode

“…Besides the additive Al reflection peaks deriving from the Al foil, all of the residual peaks can be well indexed to trigonal Na 4 MnV(PO 4 ) 3 without any impurities (Figure 5b), which indicates its perfectly maintained lattice structure and no side reactions happening during deep cycling. [41,42] The fitting results can be seen from Table S3 (Supporting Information). Therefore, it is reasonable to conclude that the outstanding cycling stability of NMVP@C@GA should be ascribed to the structure of robust interconnected GA framework-supported in situ carbon-coated NASICON-Na 4 MnV(PO 4 ) 3 , which can not only endure the current attack even at high rate of 20 C, but can also buffer the lattice strain and volume change caused by Na + diffusion behaviors to prevent the electrode from structural degradation.…”