Tuning anisotropic ion transport in mesocrystalline lithium orthosilicate nanostructures with preferentially exposed facets

Abstract

Li 2 TMSiO 4 (TM = Mn, Fe, Co, etc.) is regarded as a new class of cathode materials for next generation Li-ion batteries because of the theoretical possibility of reversible deintercalation of two Li ions from the structure (ca. 330 mA hg −1). Nevertheless, the silicate cathode still suffers from low electronic conductivity, slow Li ion diffusion and structural instability upon deep cycling. To solve these problems, for the first time, we propose a rational design of mesocrystalline Li 2 FeSiO 4 hollow discoids with an ordered single-crystal-like structure and highly exposed (001) facets. The Li 2 FeSiO 4 mesocrystals display a near theoretical discharge capacity, superior rate capability and good cycling stability. The enhanced Li storage performance is ascribed to the unique structural features with a large surface area generated from the hollow mesocrystal structure and a shortened Li + diffusion path along (001) exposed facets. This new facile, elegant synthesis method that enables the manipulation of crystal growth and subsequent improvements in the electronic and ionic kinetics and structural integrity should have a positive impact on the research and development of silicate materials as promising cathodes for next generation Li-ion batteries.

Prediction Clue on the Fading Capacity of Multi-Walled Carbon Nanotube-Decorated Li2(Fe1–xTix)SiO4/C High-Performance Cathode Materials

“…All the samples exhibit an XRD pattern analogous to that of the bare LFS/C nanocathode. All the crystallographic planes are indexed to the orthorhombic structure with the Pmn 2 1 space group, which is consistent with previous reports ,, and matched well with ICDD file no. 01-076-8751.…”

“…The coated foil was dried in an incubator oven at 60 °C for 12 h and cut into small electrodes using an electrode cutter to use as the working electrodes for the fabrication of coin cells. 1 M of LiPF 6 (lithium hexafluorophosphate) dissolved in ethylene carbonate and dimethyl carbonate All the crystallographic planes are indexed to the orthorhombic structure with the Pmn2 1 space group, which is consistent with previous reports 16,20,21 and matched well with ICDD file no. 01-076-8751.…”

New Horizons of Nonclassical Crystallization

“…The mesocrystals had a nearly theoretical discharge capacity, superior rate capability, and also a good cycling stability, which suggests such material superstructures as high performance electrode for next generation Li-ion batteries. This outstanding performance could be achieved by shortened Li + diffusion paths along the exposed {001} facets as well as a large surface area generated by a hollow mesocrystal structure . This underlines the potential of mesocrystals as outstanding materials in energy and catalysis applications due to the combination of high surface areas and exposure of reactive faces.…”

“…Another recent example of outstanding mesocrystal performance is reported for lithium orthosilicate (Li 2 TMSiO 4 with TM = Mn, Fe, Co) as cathode materials for Li-ion batteries . The mesocrystals had a nearly theoretical discharge capacity, superior rate capability, and also a good cycling stability, which suggests such material superstructures as high performance electrode for next generation Li-ion batteries.…”

A Critical Review on Electrochemical Properties and Significance of Orthosilicate‐Based Cathode Materials for Rechargeable Li/Na/Mg Batteries and Hybrid Supercapacitors

“…The 16.7 % carbon embedded Li 2 FeSiO 4 /C exhibited the discharge capacity of 165, 151, 111 and 96 mAh g À 1 at 0.2 C, 0.5 C, 5 C and 10 C rates. Ding et al [76] developed the mesocrystalline Li 2 FeSiO 4 hollow discoids which exhibited higher discharge capacity and rate capability (Figure 3(v) and viii) than the Li 2 FeSiO 4 particles prepared by sol-gel method (Figure 3vi and ix). The carboncoated Li 2 FeSiO 4 hollow spheres were crafted using hollow silica spheres as both reactant and template, and phenolic resin as a carbon source.…”