CoO nanoparticles anchored on porous pinecone-derived activated carbon as anodes for high-performance lithium and sodium-ion batteries

In this work, a new nanocomposite system based on CoO nanoparticles (NPs) anchored on pinecone-derived activated carbon (PAC), denoted as CoO(x)@PAC, is synthesized by facile ball-milling and sonication processes followed by annealing. H₃PO₄ is employed as an activation agent to activate the porous carbon derived from pinecone. The loading amount of CoO is varied to obtain the optimum electrochemical performances. Among the nanocomposites, the CoO(20)@PAC delivers a discharge capacity of 886 mA h g⁻¹ after 100 cycles at a current density of 100 mA g⁻¹ when employed as an anode in lithium-ion batteries (LIBs). At higher current rate of 1000 mA g⁻¹, the anode provides an enhanced discharge capacity of 456.6 mA h g⁻¹ after 200 cycles with 99 % capacity retention compared to the 4th cycle capacity. In sodium-ion batteries (SIBs), the CoO(20)@PAC anode delivers a discharge capacity of 290 mA h g⁻¹ at 50 mA g⁻¹. The same nanocomposite anode provides a discharge capacity of 120 mA h g⁻¹ after 900 cycles at a current density of 500 mA g⁻¹. The CoO(20)@PAC nanocomposite shows a great potential as an anode for both LIBs and SIBs, due to its higher capacity, exceptional rate capability, longer cycle life, and a Coulombic efficiency exceeding 99 %.