Lithium metal phosphates (olivines) are emerging as long-lived, safe cathode materials in Li-ion batteries. Nano-LiFePO4 already appears in high-power applications, and LiMnPO4 development is underway. Current and emerging Fe- and Mn-based intercalants, however, are low-energy producers compared to Ni and Co compounds. LiNiPO4, a high voltage olivine, has the potential for superior energy output (>10.7Wh in 18650 batteries), compared with commercial Li(Co,Ni)O2 derivatives (up to 9.9Wh). Speculative Co and Ni olivine cathode materials charged to above 4.5V will require significant advances in electrolyte compositions and nanotechnology before commercialization. The major drivers toward 5V battery chemistries are the inherent abuse tolerance of phosphates and the economic benefit of LiNiPO4: it can produce 34% greater energy per dollar of cell material cost than LiAl0.05Co0.15Ni0.8O2, today's “standard” cathode intercalant in Li-ion batteries.