Ziji Lin

A ( LiFePO4 – AC ) ∕ Li4Ti5O12 Hybrid Battery Capacitor

In this work, we synthesized a composite cathode material containing LiFePO 4 and activated carbon (AC), which is abbreviated as LAC, by a solid-state reaction, and assembled a hybrid battery-capacitor LAC/Li 4 Ti 5 O 12 . The electrochemical performances of the hybrid battery-capacitor LAC/Li 4 Ti 5 O 12 were characterized by cyclic voltammograms, constant current charge-discharge, rate charge-discharge, and cycle performance testing. The results show the hybrid battery-capacitor LAC/Li 4 Ti 5 O 12 has advantages of the high rate capability of hybrid capacitor AC/Li 4 Ti 5 O 12 and the high capacity of battery LiFePO 4 /Li 4 Ti 5 O 12 . It is also proven that the hybrid battery-capacitor LAC/Li 4 Ti 5 O 12 is an energy storage device where the capacitor and the secondary battery coexist in one cell system.

Kinetic analysis of one-step solid-state reaction for Li4Ti5O12/C.

The kinetics of one-step solid-state reaction of Li(4)Ti(5)O(12)/C in a dynamic nitrogen atmosphere was first studied by means of thermogravimetric-differential thermal analysis technique at five different heating rates. According to the double equal-double steps method, the Li(4)Ti(5)O(12)/C solid-state reaction mechanism could be properly described as the Jander equation, which was a three-dimensional diffusion with spherical symmetry, and the reaction mechanism functions were listed as follows: f(α) = (3)/(2)(1 - α)(2/3)[1 - (1 - α)(1/3)](-1), G(α) = [1 - (1 - α)(1/3)](2). In FWO method, average activation energy, frequency factor, and reaction order were 284.40 kJ mol(-1), 2.51 × 10(18) min(-1), and 1.01, respectively. However, the corresponding values in FRL method were 271.70 kJ mol(-1), 1.00 × 10(17) min(-1), and 0.96, respectively. Moreover, the values of enthalpy of activation, Gibbs free energy of activation, and entropy of activation at the peak temperature were 272.06 kJ mol(-1), 240.16 kJ mol(-1), and 44.24 J mol(-1) K(-1), respectively.

Polarization behaviour of steel/solid electrolyte interface and the anti-corrosion effect

This paper investigates the potential application of Na-beta-alumina and silica gel electrolyte containing various phosphorates for steel protection under environmental conditions where no any other continuous ion conducting materials would exist on the steel surface. The experimental results showed that the open circuit potential of the steel/solid electrolyte interface versus the platinum reference electrode originated from the corrosion of steel by oxygen gas and water that penetrated through the electrolytes. It was revealed that the cathodic and anodic polarization behaviour of steel was affected by factors such as the nature of electrolyte, the temperature and the relative humidity. Effective cathodic protection has been demonstrated, with some indications of the change at the steel/solid electrolyte interface provided by complex impedance analyses.