Phosphorus-doped porous carbon derived from rice husk as anode for lithium ion batteries

We developed a simple and scalable chemical method to obtain phosphorus-doped porous carbon (P-PC-RH) by optimized acid treatment and thermal annealing of rice husk with triphenylphosphine (TPP). After doping with phosphorus (doping level of ∼4.14 at% P), the P-PC-RH electrode increases by almost half the reversible capacity (757 mA h g^-1 after 100 cycles at 100 mA g^-1) of porous carbon without phosphorus doping (PC-RH-x, x = 2, 4, 6). When cycled at a high current of 2000 mA g^-1, it still delivers a reversible specific capacity of 382 mA h g^-1. The improved electrochemical performance of P-PC-RH is attributed to the synergetic effect of the 3D interconnected porous structure and phosphorus doping, which can maintain perfect electrical conductivity throughout the electrode and enhance electrochemical activities for lithium storage.