Introduction

Energy production and storage has been one of the hottest scientific topics in recent years. With the irreversible consumption of fossil fuel resources and increasingly severe environmental problems, renewable and clean energy source such as solar and wind energy are rapidly developing. However, some challenges are accompanied especially on how to smoothly and safely integrate the intermittent renewable energy into the grid. The application of a proper large-scale energy storage system will be extremely important and urgently needed. Among diverse potential energy storage technologies, electrochemical secondary batteries are competitive due to the advantages such as high energy conversion efficiency and simple maintenance. The major parameters for stationary batteries are low cost, high safety and long life span.