A lithium transition metal phosphate material comprising lithium iron phosphate doped with very precise amounts of aluminium dopant, the material having formula LiyFe1-xAlxPO4, in which 0.8≤y≤1.2 and 0.0120≤x≤0.0180. When x is within this range, the capacity of the material can be improved, and good or excellent distribution of aluminium in the lithium metal phosphate is observed.