Rapid advances in small satellite (often referred to as CubeSats) technology are providing opportunities for space exploration to a wide range of users (in particular universities) at substantially reduced costs. Many of the capabilities provided by larger satellites and spacecraft (>2000 kg) are now available through small satellite technologies. Ongoing improvements in attitude control, propulsion, advanced communications, and scientific instrumentation continue to enhance their benefits, even within such strict volume and mass constraints. With such advances in CubeSat technologies, the power and energy demands have also increased dramatically, necessitating the need for larger deployable solar arrays, lower power electronics, efficient energy storage systems, and even energy transfer/harvesting systems. In terms of energy storage, more advanced battery chemistries with higher energy densities and higher power capabilities over a wider operating temperature range are also a fundamental need. There already exist today numerous commercially available energy storage options suitable for CubeSat applications, although many missions rely on custom designs. Similar to standard satellite design, the selection of an appropriate energy storage system is driven by mission requirements related to power, energy, and lifetime. This paper will provide a general review of performance capabilities of state-of-the-art lithium-ion battery technologies, as well as other advanced energy storage systems for small satellite applications.