Electrochemical Properties of Li_3Fe_(o.2)Mn_(0.8)C0_3P0_4 as a Li-Ion Battery Cathode

摘要

Previously conducted high-throughput ab initio calculations have identified carbonophosphates as a new class of polyanion cathode materials. Li_3MnCO_3PO_4 is the most promising candidate due to its high theoretical capacity and ideal voltage range. However, a major limitation of this material is its poor cyclability and experimentally observed capacity. In this work we synthesize Li_3Fe_(o.2)Mn_(o.8)CO_3PO_4 to combine the high theoretical capacity of Li_3MnCo_3PO_4 with the high cyclability of Li_3FeCO_3PO_4. Li_3Fe_(o.2)Mn_(o.8)CO_3PO_4 outperforms Li_3MnCO_3PO_4 in cyclability, and shows little capacity fade over 25 cycles. The observed reversible capacity of 105 mAh/g is slightly greater than in Li_3FeCO_3PO_4, and occurs at a higher average voltage.