Pitch-based carbon anode for high-energy and long-life sodium-ion battery

Abstract

Pitch-based carbon generally demonstrate remarkable electrochemical performance for sodium-ion batteries (SIBs). In this paper, the medium temperature pitch is successively subjected to heat treatment under high pressure, extraction of toluene to remove soluble matter, and carbonization of toluene insoluble matter, to prepare the anode material, named pitch toluene insoluble anode (PTIA). The PTIA is characteristic of the coral-like morphology distributed with 100−200 nm pore channels and 2−3 nm mesopores for electrolyte immersion, and the disordered carbon structure is interwoven with graphitic carbon for sodium-ion insertion/desertion and electron transmission. In the PTIA half battery, the reversible specific capacity reaches 276.9 mAh g−1 at 0.1 A g−1 after 300 cycles with a coulombic efficiency of 99.22%. Importantly, the PTIA exhibits good compatibility with vanadium sodium phosphate (NVP) cathode materials, enabling a battery PTIA//NVP to achieve a capacity density of 154 mAh g−1, an energy density of 246.7 Wh kg−1 and a power density of 4800 W kg−1 for 1000 cycles at a current density of 3 A g−1 (16−18 C). The battery has a certain working efficiency at -10−70°C.