H 4 FePO 4 ·H 2 O is synthesized by both co-precipitation and rheological phase methods. The as-synthesized compounds have been characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The electrochemical properties of NH 4 FePO 4 ·H 2 O as anode were initially investigated with a comprehensive battery testing system. The results showed that NH 4 FePO 4 ·H 2 O featured different electrochemical performances as synthesized by the two different methods. The NFP-1 sample synthesized by co-precipitation method had higher initial capacity (1406.8 mAh·g −1 ) than that of the NFP-2 (1247.9 mAh·g −1 ) sample synthesized by rheological method. After 100 cycles, NFP-1 showed higher reversible capacity (523.4 mAh·g −1 ) than that of NFP-2 (210.3 mAh·g −1 ) within the voltage range of 0.01 to 3.00 V (vs. Li + /Li) at current density of 100 mA·g −1 . The results suggested that NH 4 FePO 4 ·H 2 O prepared by co-precipitation is a novel and promising anode material for lithium-ion battery application.