Self-adaptive FeP@C nanocages for reversible and long-term lithium-ion batteries

Till date, the lithium-ion battery still remains the principal and most widely studied rechargeable energy storage device. However, drawbacks including insufficient rate and cycling performance are hindering its further development. The aforementioned drawbacks can be attributed to the unstable interface and sluggish charge storage kinetics of electrode materials. Hence, endowing electrode materials with stable interface and rapid ion/electron diffusion kinetics are effective methods to solve these problems. Herein, by tuning the antihunt interface, a high capacity self-adaptive FeP@C nanocages with fast kinetics are constructed through a self-template method and an etching process. The obtained FeP@C nanocages show a high capacity (~900 mAh g⁻¹ at 0.2 A g⁻¹) and superior rate performance (532 mAh g⁻¹ at 10 A g⁻¹). Impressively, a stable capacity of 680 mAh g⁻¹ is maintained even after a long-term cycling of 800 times at 0.5 A g⁻¹. Moreover, the fast kinetics and lithium storage mechanism are confirmed by quantitative analysis and ex-situ synchrotron high energy X-ray diffractions (HEXRD).