Lithium-ion battery anode used as silicon particles were obtained from different major suppliers, and they were characterized by different spectroscopic techniques and evaluated by electrochemical experiments. Correlations between the key physical parameters and electrochemical properties of the silicon particles were investigated. Silicon particle size, surface oxygen content, -OH content and physical appearance are found to strongly influence the electrochemical properties of the Si anode. The particle size of 100 nm has great promise for the practical application of Si nanoparticles in the lithium-ion battery industry. An inverse correlation between the oxygen content and the reversible capacity or first coulombic efficiency was obtained. The -OH content by surface treatment contributes to enhanced cycling stability by the improved affinity between the Si particle and the water-soluble binder. Spherical Si particles perform better compared to irregular particles, and agglomeration dramatically decreases the cycling stability of the Si anode. Among the investigated Si particles, the sample that exhibited a reversible capacity of more than 2500 mAh g⁻¹, a first coulombic efficiency of 89.26% and an excellent cycling stability, has great potential for use in the battery industry.

Spinel LiNi_0.5Mn_1.5O₄ (LNMO) cathode material doped with Ti and La co-doping were synthesized through a solid-state method. The bi-functions of the Ti and La co-doping is realized. On the one hand, the stability of the LiNi_0.5Mn_1.5O₄ crystal structure is enhanced and the Mn³⁺ interference inside the material is reduced by the Ti doping. On the other hand, the co-doped La contributes to the formation of Li_0.5La_0.5TiO₃ (LLTO) superionic conductor incorporated in the bulk LiNi_0.5Mn_1.5O₄ phase, thereby enhancing the Li diffusion. With the help of XRD, FTIR, SEM and STEM techniques, La and Ti in the crystallographic structure and the dispersion of the LLTO superionic conductor in the bulk LNMO spinel are discussed. At the optimized molar ratio of 20:1 between LNMO and LLTO, the composite exhibits the best electrochemical performances in terms of the reversible capacity, rate capability and cycling stability. The lithium ion diffusion coefficient in the bulk LNMO phase is tripled by the LLTO superionic conductor incorporation.