Boron-Doped Pine-Cone Carbon With 3D Interconnected Porosity for Use as an Anode for Potassium-Ion Batteries With Long Life Cycle

Abstract

Potassium-ion batteries (KIBs) have received widespread attention as an alternative to lithium-ion batteries because of their low cost and abundance of potassium. However, the poor kinetic performance and severe volume changes during charging/discharging due to the large radius of potassium leading to low capacity and rapid decay. Therefore, development of anode materials with sufficient space and active sites for potassium ion deintercalation and desorption is necessary to ensure structural stability and good electrochemical activity. This study prepared boron-doped pine-cone carbon (BZPC) with 3D interconnected hierarchical porous in ZnCl2 molten-salt by calcination under high temperature. The hierarchical porous structure promoted the penetration of the electrolyte, improved charge-carrier diffusion, alleviated volume changes during cycling, and increased the number of micropores available for adsorbing potassium ions. In addition, due to B doping, the BZPC material possessed abundant defects and active centers, and a wide interlayer distance, which enhanced the adsorption of K ions and promoted their intercalation and diffusion. When used as the anode of a KIB, BZPC provided a high reversible capacity (223.8 mAh g−1 at 50 mA g−1), excellent rate performance, and cycling stability (115.9 mAh g−1 after 2000 cycles at 1 A g−1).

Intrinsic carbon structure modification overcomes the challenge of potassium bond chemistry

“…Wen et al 138 prepared boron-doped pine-cone carbon (BZPC) with a 3D interconnected hierarchical porous structure using boric acid as the dopant sources by calcination under high temperature. Benefiting from the doping of boron atoms, the as-prepared BZPC generated numerous active sites and defects for K + adsorption, an expanded interlayer spacing and a hierarchical porous structure to promote the penetration of the electrolyte, which leads to a high reversible capacity of 223.8 mA h g −1 at 50 mA g −1 , superior rate capability and superior capacity retention of 115.9 mA h g −1 at 1 mA g −1 after 2000 cycles for PIBs.…”

Plasma-Doped Carbon-Based Anode Materials in Potassium Ion Batteries: A Review of Current and Future Prospects

“…[8,9] Highperformance anode materials are the key to the development of potassium ion batteries (PIBs), carbon materials, transition metal oxides, alloy materials, and other composites that have received extensive attention as anode materials for PIBs. [10] Carbon materials, such as graphite, soft carbon, hard carbon, reduced graphene oxide, and expanded graphite, are the most interesting anode materials due to their sustainability and low cost which makes them great candidates for commercial anode materials. For example, the electrochemical embedding of K+ in graphite is now confirmed, although K+ has a larger Shannon's ionic radius (1.38 Å) than Na+ (1.02 Å) and Li+ (0.76 Å) and Na+ cannot be reversibly embedded without prior graphite swelling or cosolvent molecules.…”