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A free-standing honerycomb-like N doped carbon (FHNC) was fabricated by one-step carbonization and activation of the commercial melamine foam loading coal tar pitch and KOH. The as-prepared FHNC exhibits three-dimensional interconnected architecture with hierarchical honeycomb-like structure, which has a large specific surface area of 3105 m2 g−1. The specific capacitance of FHNC is 280.3 F g−1 at 1 A g−1, and still maintains 185.4 F g-1 at 40 A g−1, indicating the good rate capability. • A free-standing honeycomb-like N doped carbon (FHNC) was fabricated by the commercial melamine foam and coal tar pitch. • FHNC electrodes have a large specific surface area of 3105 m2 g−1. • The specific capacitance of FHNC is 280.3 F g−1 at 1 A g−1. • The supercapacitors show 10.1 Wh kg−1 at a power density of 250 W kg−1. • The capacity retention of supercapacitor device is 96.3% after 10,000 cycles. A free-standing honeycomb-like N doped carbon foam (FHNC) is fabricated by one-step carbonization and activation of the commercial melamine foam loading coal tar pitch and KOH. The as-prepared FHNC exhibits the three-dimensional (3D) interconnected architecture with hierarchical honeycomb-like structure, which has a large specific surface area of 3105 m2 g−1. The specific capacitance of FHNC reaches up to 280.3 F g−1 at 1 A g−1, and still maintains 185.4 F g−1 at 40 A g−1, indicating the excellent rate capability. Additionally, the assembled symmetrical supercapacitor demonstrates the maximum energy density of 10.1 Wh kg−1 at a power density of 250 W kg−1, and excellent cycling stability (96.3% capacitance retention after 10,000 charge-discharge cycles at 5 A g−1). The outstanding electrochemical performance is assigned to the unique 3D interconnected architecture that endow the large accessible surface area, and rapid transfer pathway for ion and electron. [ABSTRACT FROM AUTHOR]

[Display omitted] • A scalable, facile, and low-cost technology constructed the porous structure. • The influence of copper content on initial coulombic efficiency was explored. • The effect of porosity on the stability of the composite electrode was studied. • Si/Cu/void@C-14 anode exhibited a high rate and long cycle durability. Silicon is an advanced anode material for lithium-ion batteries due to its ultra-high theoretical capacity. However, its commercial application is limited by the enormous volume change and low electrical conductivity. Herein, we synthesize a copper-doped silicon/carbon porous composite that can effectively solve the current dilemma. Uniform anchoring of copper particles on silicon significantly improves the electronic conductivity of composites. By adjusting the content of copper, the initial coulombic efficiency is increased substantially from 60.7 % to 87.6 %. The effect of porosity on the electrochemical properties is systematically studied. The optimized Si/Cu/void@C-14 anode exhibits excellent rate capability (529.3 mAh g−1 at 2 C) and cycle stability (1076.2 mAh g−1 after 300 cycles). The reasons are that the Li+ diffusion coefficient is increased effectively to 3.32 × 10-10-2.54 × 10-9 cm2 s−1, and the volume expansion rate is reduced vastly to 8.8 %. In addition, the full cells coupling LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathode with perlithiated Si/Cu/void@C-14 anode provide a high energy density of 491.5 Wh kg−1 after 100 cycles. It is worth noting that the Si/Cu/void@C-14 composite is synthesized with low-cost raw materials through facile and scalable processes, revealing that the composites have promising potential as high capacity anode materials in a commercial application. [ABSTRACT FROM AUTHOR]