Mitigation of Jahn–Teller distortion and Na+/vacancy ordering in a distorted manganese oxide cathode material by Li substitution

Li-Substitution in P′2-Na0.67MnO2 mitigates the anisotropic change of Mn–O bonds and Na/vacancy ordering, and hence significantly promotes its cycling stability and rate capability as a cathode material for sodium-ion batteries.

Microstructure and Piezoelectricity of (Na,K,Li)(Nb,Sb)O3–(Bi,Na)(Sr)ZrO3–BaZrO3 Ceramics

In this paper, (Na,K)1−xLi.x(Nb,Sb)O3–(Bi,Na)(Sr)ZrO3–BaZrO3 ceramics were fabricated with x(= Li) substitution by two-step sintering method, and their physical characteristics were investigated. When Li substitution was added to the ceramics, piezoelectric constant (d33) and electromechanical coupling factor (kp) were rapidly reduced. However, mechanical quality factor (Qm) was enhanced. For the KNN-BNZ((K,Na)(Nb)O3–(Bi,Na)(Sr)ZrO3) ceramics with Li(x) = 0 substitution, the best physical properties of d33 = 300 [pC/N], kp = 0.40, Qm = 33 and dialectic constant (εr) = 2430 were shown, respectively. Additionally, the KNN-BNZ ceramics with Li(x) = 0.02, the d33 of 246[pC/N], the kp of 0.37, the Qm of 42 and the εr of 2090 appeared, which were suitable for the low-loss piezoelectric actuator.

Effect of Li Substitution in MgO Nanostructured on Band Gap Energy via Combustion Synthesis Method

Preparation of MgO and Mg0.9Li0.2O materials using self-propagating combustion method are done to investigate the effect of substitution doping on the band gap energy. The synthesis condition has been optimized to obtain pure and single phase of MgO and Mg0.9Li0.2O materials and was confirmed by X-Ray Diffraction (XRD). The morphology obtained from field emission scanning electron microscopy (FESEM) is spherical and rounded polyhedral shape with agglomeration of crystallites for MgO and Mg0.9Li0.2O materials respectively. The crystallite size of MgO and Mg0.9 Li0.2O samples is between 50 nm to 120 nm and 200 nm to 1500 nm respectively. The band gap was determined by UV-Vis NIR spectrophotometer and it was found that the band gap obtained for MgO nanostructure is 6.10 eV which is lower than bulk MgO of 7.8 eV. The presence of Li in the MgO had caused changes in morphology, crystallite size and band gap narrowing to 3.83 eV.