Galvanic replacement synthesis of amorphous Sb confined into N,P-doped biomass carbon microspheres with enhanced sodium storage capability

Alloying-type anode materials have been demonstrated to be potential alternatives for the sodium ion batteries (SIBs). Nevertheless, the serious capacity decay inhibits their practical application. Herein, alloying-typed amorphous Sb species confined into N,O,P-doped biomass carbon microsphere (Sb@BCM) through Sb-O-C bonds is prepared via in-situ galvanic replacement of the Ni nanoparticles wrapped into the BCM (Ni@BCM), which is obtained from the hydrothermal and carbonization reaction with the Ni 2+ and porphyra. Benefitted from the optimized Sb species anchoring, stable Sb–O–C bond and N,O,P-doped carbon skeleton, Sb@BCM-3 anode exhibits enhanced reaction kinetics and cycling stability in SIBs. Sb@BCM-3 anode can deliver high rate capability of 210.0 mAh g −1 at 5.0 A g −1 and stable capacities of 171.1 mAh g −1 at 1.0 A g −1 over 1000 cycles. The fast sodium storage capability should be promoted by the pseudo-capacitive contribution. And in the Sb@BCM-3//Na 3 V 2 (PO 4 ) 3 @C full cell, a capacity of 121.2 mAh g −1 can be retained at 0.1 A g −1 over 50 cycles. Moreover, the ex-situ X-ray diffraction measurement illustrates the alloying reaction mechanism and the high reversibility for the Sb@BCM-3, which can guarantee the high capacity and good cycling stability. This study offers a method to enhance Sb anode performance through interfacial bonding with carbon.