Dual‐phase structure design of Mn‐site nickel doping Li ₂ MnSiO ₄ @C cathode material for improved electrochemical lithium storage performance

Abstract

The lithium transition metal orthosilicates (Li 2 MnSiO 4 ) compounds are considered key materials for the next-generation lithium-ion batteries (LIBs). However, they exhibit poor electronic conductivity and structural stability. Herein, the dual-phase (Pmn2 1, and Pn) coexisting Li 2 Mn 1−x Ni x SiO 4 @C is prepared successfully via a two-step calcination process to address the aforementioned problems. The orthorhombic Pmn2 1 and Pn phase are expected to bring well solid-state Li diffusion properties (D Li + ) and structural stability for electrode material, respectively. Also, the Ni doping and carbon coating are expected to raise electronic conductivity. Then, the electrochemical performance of LIBs utilizing LiMn 0.995 Ni 0.005 SiO 4 @C, LiMn 0.985 Ni 0.015 SiO 4 @C, and LiMn 0.92 Ni 0.08 SiO 4 @C (ZNi-02 to ZNi-04) as cathode materials are investigated and compared with that of the LiB using Li 2 MnSiO 4 @C (ZNi-01). The ZNi-04 sample-based LiB shows well D Li + and a peak discharge capacity as high as 188.4 mAh g −1 . In addition, the ZNi-04 sample can still maintain a capacity of about 80 mAh g −1 at rate of 8 C. Such excellent electrochemical performance is ascribed to the synergistic effect of the dual-phase coexistence, the proper amount of Ni doping, and surface coating of carbon, which enhances the electrical conductivity and structural stability. Thus, Li 2 Mn 1−x Ni x SiO 4 @C has broad application chances as a high-performance LIBs electrode material.

Aqueous synthesis of Li2MnAO4/C (A = Si, Ge) as positive electrode active materials for lithium-ion batteries by acid–base reaction

“…For example, this synthesis method can be combined with metal substitution, which is an effective strategy for improving the battery performance. 21–23 Metal-substituted materials Li 2 Mn 0.8 Fe 0.2 SiO 4 /C and Li 2 Mn 0.8 Fe 0.2 GeO 4 /C could also be prepared by the same process. Fig.…”

A critical review on orthosilicate Li2MSiO4 (M = Fe, Mn) electrode materials for Li ion batteries

“…Zhan et al [207] studied effect of Ni doping at Mn site on electrochemical performance of LMS. Li 2 Mn 1−x Ni x SiO 4 (x = 0, 0.005, 0.015, and 0.08).…”

Synthesis and Characterization of Li2Mn0.8Ni0.2SiO4/Mn3O4 Nanocomposite for Photocatalytic Degradation of Reactive Blue (RB5) Dye

“…Figure 4b and c show that for LMS and LMNS, the O-Li-O bending vibration of LiO 4 tetrahedra corresponds to the vibrational peak of 420 cm −1 [31] The vibrational peaks in the 480-590 cm −1 band represent the O-Si-O bending vibrations, whereas the vibrational peaks in the 860-927 cm −1 band represent the stretching vibrations of the Si-O bonds in SiO 4 tetrahedra [32]. The peaks above 1000 cm −1 could be attributed to the C-O from the impure phase [36]. Figure 4d and e show the FTIR spectra of LMS/M3 and LMNS/M3 exhibiting the same spectrum as LMS.…”