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Cobalt-free Li-rich Mn-based cathode materials are considered to be the next generation of Li-ion batteries due to low cost, high discharge capacities and high safety feature. However, there are still several serious issues that need to be solved urgently, such as low initial coulombic efficiency, low rate capability, poor cycling performance and voltage fading. Na doping or substitution is introduced to improve the electrochemical performance of Li1.2Mn0.6Ni0.2O2 cathode material, which is synthesized by sol-gel method. The effect of Na doping or substitution on the morphological, structural and electrochemical properties was systematically studied and analyzed by scanning electron microscope (SEM), X-Ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), cell test system and electrochemical workstation. These results illustrate that lattice layer spacing is enlarged by Na doping or substitution, which is beneficial for the diffusion of Li-ion, and the voltage fading is successfully suppressed. The best electrochemical properties were obtained when Na doping, which is attributed to the stronger structural stability and better reversibility of Li+ during the initial charge and discharge process.

A constructive method is developed for designing simultaneously quadratically stabilizing state feedback controllers for a collection of single-input discrete-time nonlinear systems. In the context of quadratic control Lyapunov functions a necessary and sufficient condition for the existence of simultaneously quadratically stabilizing state feedback laws is derived. An explicit formula for constructing continuous simultaneously stabilizing controllers is presented. The obtained results are verified by a numerical example. [ABSTRACT FROM AUTHOR]

This note develops a novel method for designing simultaneous H∞ state feedback controllers for a collection of single-input nonlinear systems. Based on the Katman-Yakubovich-Popov Lemma, necessary and sufficient conditions for the existence of simultaneous H∞ controllers are derived by the control storage function approach. A universal formula for constructing continuous, time-invariant, simultaneous H∞ state feedback controllers is presented. [ABSTRACT FROM AUTHOR]

In this note, based on the control Lyapunov function approach, a new method for solving the feedback stabilization problem of switched systems that are switching arbitrarily between two multiinput nonlinear subsystems is introduced. Necessary and sufficient conditions for the existence of globally uniformly asymptotically stabilizing state feedback controllers are derived. Additionally, a universal formula for constructing implementable stabilizing controllers is given when the presented conditions hold. One numerical example is given to illustrate the results [ABSTRACT FROM AUTHOR]

This note deals with the stabilization problem of single-input polytopic nonlinear systems. The robust control Lyapunov function approach is used to derive a sufficient condition for the existence of time-invariant, continuous, asymptotically stabilizing state feedback controllers. The obtained sufficient condition is proven also necessary for the existence of stabilizing state feedback controllers such that the closed-loop system has a robust Lyapunov function for all possible uncertainties. In addition, a universal formula for constructing stabilizing controllers when the presented sufficient condition is met is provided. The results are illustrated by a numerical example. [ABSTRACT FROM AUTHOR]

This paper presents a novel method for designing a controller that simultaneously stabilizes a collection of single-input nonlinear systems. The control Lyapunov function approach is used to derive necessary and sufficient conditions for the existence of time-invariant simultaneously stabilizing state feedback controllers. Additionally, a universal formula for constructing a continuous simultaneously stabilizing controller when the provided sufficient condition is satisfied, is presented. For any collection of second-order (and third-order) feedback linearizable systems in canonical form, global simultaneous stabilization via a single state feedback controller is shown to be always possible. Two examples are included for illustration. [ABSTRACT FROM AUTHOR]

Considers the standard H-infinity-control problem for more general nonlinear systems modeled by equations in which the penalty output and the measured output are in general functions of the state x. Characterization of a family of H-infinity controllers via output feedback as well as state feedback.