Several factors are combining to create significant growth in the secondary lithium-ion battery market, according to an analysis by Frost & Sullivan, World Secondary Lithium-Ion Battery Market. Latest figures show that the market earned revenues of $5.89 billion on shipments of nearly 1.76 billion secondary units. The firm estimates that this will grow to nearly 3.99 billion units in 2013. Increased investment in technological developments and innovations are likely to make these batteries more efficient, according to Frost & Sullivan. "Technical innovations such as thin-film batteries and high-energy-density lithium-ion batteries create bright growth prospects for lithium-ion batteries," analyst Suba Swaminathan said in a statement. "High energy and power density, along with the low weight of these batteries, are some of the key factors that propel market demand." Other factors include the increased use of sophisticated multi-tasking consumer electronic gadgets and the surge in demand for high-efficiency power sources for portable industrial applications. Despite these positive trends, safety concerns related to the use of lithium-ion batteries in high temperatures are likely to dampen market growth, according to Frost & Sullivan. As a result, lithium-ion batteries that can withstand high temperatures without causing thermal runaway are expected to hit the market in the next two to three years.