Ionic Conductive Interface Boosting High Performance LiNi_0.8Co_0.1Mn_0.1O₂ for Lithium Ion Batteries

Abstract

LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM) is a highly prospective cathode material for high energy density Li-ion batteries (LIBs). Nevertheless, poor cycling performance and rate capability at high cutoff voltages have dramatically blocked its further commercialization. In this study, an ionic conductive interface has been demonstrated to enhance the NCM electrochemical property at the high cutoff voltage of 4.5 V on account of the existence of a Li-ion conductor of Li 2 SnO 3 . In comparison to SnO 2 , Li 2 SnO 3 causes a smoother Li-ion diffusion at the engineered interfaces, lower polarization, slower capacity drop, and voltage fading as well as better H2/H3 reversibility upon cycling. Importantly, it is confirmed that excellent diffusion is beneficial to preservation of reversible phase transition and reduction of polarization, which are directly relative to the superior cyclability and rate capability. This work reveals that building an excellent ionic diffusion interface is feasible for Ni-rich cathodes with simultaneous high capacity and stable cyclability. KEYWORDS: LiNi 0.8 Mn 0.1 Co 0.1 O 2 cathode, SnO 2 , Li 2 SnO 3 , coating, lithium ion batteries

Surface Reconstruction of Ni‐Rich Layered Cathodes: In Situ Doping versus Ex Situ Doping

“…The potential difference (Δ V E ) between the oxidation peaks of the first and second cycles is directly related to the side reactions and electrochemical polarization. [ 7,13 ] Δ V E for in situ Zn‐NCM (ca. 0.114 V) is much smaller than that of the NCM and ex situ Zn‐NCM samples (−0.132 and 0.208 V).…”

“…Peak current intensities of the three electrodes has a linear relationship with the square root of applied scan rate, which is related to the diffusion‐limited de‐/intercalation process. [ 13 ] The corresponding to the phase transition of H1/M and H2/H3 are obtained for NCM, ex situ Zn‐NCM, and in situ Zn‐NCM. It is worth noting that Li + diffusion in both doped materials is improved compared to the NCM, and among them, in situ Zn‐NCM shows the best performance.…”

“…[ 35 ] of in situ Zn‐NCM is larger than that of the other materials during both charging and discharging (Figure 6e,f), which substantiates that in situ doping effectively improves Li + diffusion at the cathode surface. [ 13 ]…”

“…[ 4,11,12 ] In summary, most of these problems are mainly initiated at cathode surface, and the stability of this region largely determines the electrochemical performance of the cell. [ 4,9,13 ]…”

Enabling Superior Electrochemical Performance of Lithium-Rich Li1.2Ni0.2Mn0.6O2 Cathode Materials by Surface Integration

“…The tests of LMR, LMR-0.5, and LMR-1 are performed at different scan rates, as shown in Figure a–c. With the increase of the scan rates, the peaks assigned to anodic and cathodic moved to higher and lower potentials, respectively. − The results show that the diffusion behavior of lithium ions is mainly determined by the high rate control. Moreover, the lithium ion diffusion coefficient ( D Li + ) can be calculated using the Randles–Sevcik equation as follows …”