The development of alternative anode materials with higher volumetric and gravimetric capacity allowing for fast delithiation and, even more important, lithiation is crucial for next-generation lithium-ion batteries. Herein, the development of a completely new active material is reported, which follows an insertion-type lithiation mechanism, metal-doped CeO$_{2}$. Remarkably, the introduction of carefully selected dopants, herein exemplified for iron, results in an increase of the achievable capacity by more than 200%, originating from the reduction of the dopant to the metallic state and additional space for the lithium ion insertion due to a significant off-centering of the dopant atoms in the crystal structure, away from the original Ce site. In addition to the outstanding performance of such materials in high-power lithium-ion full-cells, the selective reduction of the iron dopant under preservation of the crystal structure of the host material is expected to open up a new field of research.