Lithium ion batteries were first commercially introduced in 1991[1]. Since their introduction, they have revolutionized consumer electronics by becoming the dominant power source for devices such as laptops and cell phones. This is mainly due to their higher energy density compared to other energy sources. Nowadays, lithium-ion batteries are becoming the subject of even greater interest, as they are the preferred energy source for electric vehicles (hybrid and otherwise). This is especially relevant considering the focus on finding zero-carbon energy sources to replace the reliance on fossil fuels for cars. Lithium-ion batteries do not contain metallic lithium. Instead, they contain a negative electrode (made of graphite), a liquid (non-aqueous) electrolyte, and a positive electrode made of a layer of lithium and transition metal oxide such as LiCoO2 (Figure 1). Once charged, the lithium ions deinterlacate from the cathode, make their way through the electrolyte, and then intercalate between the graphite layers in the anode. During discharge, the process is reversed. Since their initial introduction in 1991, numerous improvements have been made to lithium-ion technology, which have significantly improved charge and discharge speed, safety and cycle life. However, since lithium-ion batteries are the preferred power source for electric vehicles, such as Tesla's Model S, new challenges are being posed to this form of technology. Specifically, newer forms of lithium-ion batteries must be optimized for fast charge/discharge rates while being immune to overheating. In the following sections, we will look at the different approaches that have been used to optimize performance in...... half of the article ......cations have the ability to order on the octahedral sublattice. Interestingly, a disordered spinel structure appears to have a higher capacitance [24]. Partial replacement of cobalt with nickel (i.e. Li[Mn1.42N0.43Co0.16]O4) appears to reduce the formation of LixNi1-xO, which tends to degrade cellular performance during cycling [25]. Another way to improve capacity retention is to add nickel to the surface of LiMn2O4 through coatings rather than as a bulk dopant. LiFePO4 and other phosphates Phosphates (LiMPO4) with the olivine structure (Pnma) are another promising class of candidates. Here, phosphorus occupies tetrahedral sites, while transition metal M occupies octahedral sites, and lithium forms one-dimensional chains along the [0 1 0] direction [26]. The most commonly used phosphate is LiFePO4 and transforms into FePO4 when Fe2+ is oxidized to Fe3+ [27].