Rational construction of CoP@C hollow structure for ultrafast and stable sodium energy storage

The development of transition metal phosphides as potential anode materials of sodium-ion batteries has been substantially hindered by their sluggish kinetics and significant volume change during the sodiation/desodiation process. In this work, we put forward a rational design strategy to construct a hollow-structured CoP@C composite to achieve ultrafast and durable sodium energy storage. The CoP@C composite with a well-defined hollow dodecahedron architecture has been synthesized via a stepwise treatment of carbonization and pohsphorization on ZIF-67. The unique hollow carbon framework not only provides high-speed electron/ion transportation pathways for CoP to enable fast sodiation kinetics, but also accommodates large volume change to stabilize the electrode structure. As a consequence, the CoP@C composite could exhibit an ultra-high rate capability of 105 mAh·g−1 at a current density of 30 A·g−1, and a long-term cycling lifetime. The present study will pave a fresh strategy for exploring advanced high-power anode materials for sodium ion batteries.Graphical abstract