Kim, Myung Hwan Battery R&D, LG Chem Li-ion rechargeable batteries, successfully commercialized in 1991, have achieved high energy and good performance with fast development in a relatively short period of time and cause lots of our life changed. In the late 1990s, most cell phones were powered with Ni-MH batteries. But as the smart phones appeared and a lot of power consumption for the phones is required to implement a variety of features, the Li-ion batteries has become a solution for it and the IT market has been one step ahead in innovation. While the importance of clean energy was emerged due to energy depletion and environmental pollution problems and electric vehicles were on the rise in the market, perspective on the development of the electric vehicle market was not optimistic because the difficulties such as high price, short driving distance, and long charging time must be overcome simultaneously. However, with unique idea, that is, operating with seven thousands of small cylindrical Li-ion batteries, Tesla made a big hit in the electric vehicle market. Additionally, most of major auto makers have plans to launch various kinds of electric vehicles with Li-ion batteries in a few years. In the energy storage system (ESS) market, deepening the imbalance between power supply and demand makes the renewable energy market bigger. With growing ESS market of which the mainstreams are NaS, lead acid, CAES, and pumped hydro, Li-ion batteries are expected to be a promising solution. Li-ion battery technology will dominate the energy storage market for several decades with developing new materials. Energy density and power performance will be further improved and the cost will be decreased continuously. The history and development trends for major applications of the Li-ion batteries will be addressed in this talk. Keywords: Li-ion battery, clean energy, IT, electric vehicle, ESS