Phytic acid derived LiFePO 4 beyond theoretical capacity as high-energy density cathode for lithium ion battery

A glucose-derived carbon-encapsulated (GC) LiFePO4 (LFP) with internal carbon sheets (IC) composite, GC/IC/LFP, is synthesized by using phytic acid (PhyA) as a special phosphorus source. PhyA plays an important role as a structure-director, complexing agent and antioxidant, and the resulted IC contributes to improving electrochemical properties. The special morphology and microstructure of precursors and final materials are characterized and discussed in detail. The prepared GC/IC/LFP shows not only an excellent cycle performance, but an ultra-high specific capacity of 192 mA h g−1 at 0.1 C, which exceeds the theoretical capacity of LFP. A remarkable rate performance of 140 mA h g−1 at 10 C was also achieved. The energy efficiency of GC/IC/LFP can reach nearly 96% at 0.1 C.