Low-temperature performance of brominated nitrogen-doped carbon in lithium-ion batteries

Abstract

The development of appropriate anode material for lithium-ion batteries that can support operation under low ambient temperatures is necessary. Here, bromine-free and bromine-doped porous nitrogen-doped carbon materials were tested as anodes in lithium-ion batteries at the operation temperatures from 25 to −20 °C. The nitrogen-doped carbon material was synthesized from acetonitrile and calcium glutarate and demonstrated high reversible capacity of 907 mAhg⁻¹ at current density of 0.1 Ag⁻¹ and 462 mAhg⁻¹ at 2 Ag⁻¹. The content of 2 at% of bromine (Br) in forms of covalently bonded Br atoms and adsorbed Br_n⁻ molecules was achieved by interaction of material with Br₂ vapor. The brominated material showed increased capacity of 1101 mAhg⁻¹ at 0.1 Ag⁻¹ and 612 mAhg⁻¹ at 2 Ag⁻¹ due to additional lithium capture by bromine-containing functional groups. Lowering the operation temperature from 25 to −20 °C resulted in 59 % capacity retention for the initial sample and 51 % for the brominated analogue of their capacity at 2 Ag⁻¹. The high capacity retention was explained by fast kinetics of adsorption reaction of lithium with carbon electrodes due to nitrogen- and bromine-based functional groups, and high mesoporosity.