The high electrical conductivity of carbon nanotubes (CNTs) allows them to be used in small amounts as a conductive additive in lithium-ion batteries (LIBs), thereby increasing the reversible capacity of LIBs by adding more active materials to the electrode. Transition metal catalysts are used to synthesize CNTs, but if these catalysts are not at the level of a few parts per million, side reactions may occur. Thus, additional purification processes may be required. Here, CNTs are prepared using an alkali metal catalyst that can be easily removed by dissolving in water or heating, making this process environment-friendly. These CNTs grow in a cup-stacked arrangement, are longer than 5 µm, and have diameters of 10–20 nm. Their physical properties are determined using different spectroscopic and diffraction techniques, and they are electrochemically analyzed as a conductive additive in the cathode of an LIB. Unlike conventional cylindrical CNTs, cup-stacked CNTs possess numerous side planes, which offer sufficient pathways for Li-ion transport, thereby improving the electrochemical properties of the electrode. Such crystallographic characteristics result in approximately 10% higher discharge capacity at all C-rates and ~2% higher rate capability compared with those of commercial CNTs. Therefore, this strategy for producing LIBs is cost-effective and environment-friendly.