Li₂SiO₃ Modification of C/LiFe_0.5Mn_0.5PO₄ for High Performance Lithium‐Ion Batteries

Abstract

The carbon‐coated LiFe0.5Mn0.5PO4 (C/LFMP) and carbon‐coated LiFe0.5Mn0.5PO4@Li2SiO3 (C/LFMP‐LSO) could be successfully prepared by high temperature solid‐state reaction. Even though the crystal structure and morphology of C/LiFe0.5Mn0.5PO4 was not changed by Li2SiO3 coating, Li2SiO3 modification was able to facilitate the diffusion of lithium ions, resulting in an excellent rate performance and cyclic stability of C/LFMP‐1LSO (1 wt %). The reversible discharge specific capacities of C/LFMP‐1LSO are 157.6 mAh g−1 and 106.3 mAh g−1 at 0.1C and 10C, respectively. Meanwhile, the C/LFMP‐1LSO was cycled for 500 times at 5C with a capacity retention rate of 85.3 %. Furthermore, at a low temperature of 6 °C and 0.2C, the C/LFMP‐1LSO displayed good low temperature performance with a discharge specific capacity of 140.6 mAh g−1. Li2SiO3 coating was considered an effective way to boost the overall electrochemical performance of C/LFMP.

Optimizing the Electrochemical Performance of Olivine LiMnxFe1–xPO4 Cathode Materials: Ongoing Progresses and Challenges

“…The findings indicate that the optimized sample (the content of Li 3 PO 4 is 3%) yields the highest capacity of 136 mAh g –1 at 5C and capacity retention of 91.6% after 500 cycles at 2C (Figure b,c). Similarly, Liu et al successfully prepared carbon-coated LiFe 0.5 Mn 0.5 PO 4 @Li 2 SiO 3 (Figure d). The Li 2 SiO 3 coating does not alter the crystal structure and morphology of carbon-coated LiFe 0.5 Mn 0.5 PO 4 , but promotes the diffusion of Li + , resulting in an excellent rate performance (Figure e).…”

“…Lithium-ion conductor, as a solid-state material with ionic conductivity comparable to or even higher than that in liquid state, demonstrates the ability to rapidly transport Li + , 166 which has the following effects on LiMn x Fe 1−x PO 4 : (1) establishing a stable barrier coating without sacrificing interfacial Li + ; (2) inhibiting Mn dissolution and minimizing side reactions; (3) effectively suppressing the formation of Fe 2+ − Li + antisite defects. 167 In recent years, numerous lithium-ion conductors, such as Li 3 PO 4 , 97,168 LiAlO 2 , 169 Li 3 VO 4 , 170 Li 2 SiO 3 , 171 have been utilized to enhance the electrochemical performance of host particles by stabilizing the structure. Li et al 168 synthesized a hierarchical LiMn 0.8 Fe 0.2 PO 4 /C composite comodified with Li 3 PO 4 and graphite, and its morphology is shown in Figure 13a.…”

“…(d) HRTEM images and (e) rate capability of carbon-coated LiFe 0.5 Mn 0.5 PO 4 @Li 2 SiO 3 ; (f) interface structural model between LiFe 0.5 Mn 0.5 PO 4 and Li 2 SiO 3 ; (g) diffusion barriers in Li 2 SiO 3 and LiFe 0.5 Mn 0.5 PO 4 . Reproduced with permission from ref . Copyright 2022 Wiley-VCH.…”