Exposed Surface Engineering of High-voltage LiNi_0.5Co_0.2Mn_0.3O₂ Cathode Materials Enables High-rate and Durable Li-ion Batteries

Abstract

Engineering the exposed surface of primary particles is a viable strategy to enhance the charging rate and structural stability of high-voltage LiN0.5C0.2M0.3O2 (NCM) cathode materials. Herein, we have developed highly conductive Na2MoO4 and engineered the exposed surface of NCM by a simple infiltration and subsequent low-temperature melting process. Such an ingenious strategy can achieve a high-quality and uniform coating layer for effectively decreasing the side effects between electrode materials and the electrolyte with a rapid electron transfer pathway network. Consequently, the as-obtained NCM-NMO delivers improved reversible capacities of 202.5 mAh g–1 at 0.2C and 129.0 mAh g–1 at 10C in 3.0–4.5 V, which is much higher than the unmodified NCM (86.1 mAh g–1@10C). After 100 cycles at 1C, 91% reversible capacity is retained with a negligible voltage plateau and structural change. This finding demonstrates a novel concept to modify the primary particles of cathode materials by engineering their exposed surface.

Enhancing Surface and Crystal Stability of the Ni-High NCA Cathode for High-Energy and Durable Lithium-Ion Batteries

“…5b), and the peak intensity of Li x PO y F z and LiF for NCA is larger as a result of a thicker cathode-electrolyte interphase formed on the surface of NCA, 18,42 which further suggests that the Li 4 SiO 4 coating layer could alleviate a series of surface parasitic reactions during cycling. The electrode SEM images of NCA and SN-1@ NCA (Figure 5c,d) show that the morphology of the cycled NCA suffers serious damage and the secondary particles show more microcracks and pulverization phenomenon caused by the evolution of lattice parameters during de-/lithiation, and the penetration of the electrolyte into the internal fracture accelerates the deterioration of the structure, 43 while the spherical shape is well maintained after repeated cycles for SN-1@NCA, which is associated with the enhanced overall structure. XRD measurements of electrodes after 100 cycles at 1 C are also displayed in Figure S9a.…”

Enhanced Electrochemical Performance of 5V LiNi0.5Mn1.5‐xZrxO4 Cathode Material for Lithium‐Ion Batteries

“…The Li 1s spectra in Figure 2(a) show a characteristic peak at ∼53.9 eV corresponding to Li−O bond. In Figure 2(b), the O 1s spectra are composed of a strong peak at ∼530.0 eV corresponding to transition metal oxide and a weak peak at ∼531.6 eV assigned to residual Li 2 CO 3 on particle surface [35] . Figure 2(c) shows the Ni 2p spectra of both samples, where the bands at ∼855.1 eV and ∼ 872.9 eV are assigned to Ni 2p 3/2 and Ni 2p 1/2 , respectively, implying the presence of Ni 2+ , [36] and the satellite peaks at ∼861.4 eV and ∼879.6 eV are ascribed to the multiple splitting in the energy levels of nickel oxide (NiO) [37] .…”

Optimizing Both Bulk and Surface Structure of Li‐Rich Layered Cathodes for Long‐Life and Safe Li‐Ion Batteries

“…The polarization of the electrode can be revealed by the voltage intervals (∆E) between cathodic and anodic peaks in the Cyclic Voltammetry (CV) curve. [43] As shown in Figure S8d (Supporting Information), two oxidation peaks can be observed in the first cycle of Al 2 O 3 @LLO and Al 2 O 3 @LLO-600 samples. The peak at around 4.0 V corresponds to the oxidation process of Ni 2+ to Ni 4+ and Co 3+ to Co 4+ with deintercalation of Li + from Li slabs to form octahedral vacancies, while the strongest peak at about 4.6 V is related to the activation process of Li 2 MnO 3 and the deintercalation process of Li + from both Li slabs and TM slabs along with the oxidation of O 2− .…”