Adamson, A.; Väli, R.; Paalo, M.; Aruväli, J.; Koppel, M.; Palm, R.; Härk, E.; Nerut, J.; Romann, T.; Lust, E.; Jänes, A.: Peat-derived hard carbon electrodes with superior capacity for sodium-ion batteries. RSC Advances 10 (2020), p. 20145-20154
10.1039/d0ra03212c
Open Access Version
Abstract:
Herein we demonstrate how peat, abundant and cheap biomass, can be successfully used as a precursor to synthesize peat-derived hard carbons (PDCs), applicable as electrode materials for sodium-ion batteries (SIB). The PDCs were obtained by pre-pyrolysing peat at 300–800 C, removing impurities with base– acid solution treatment and thereafter post-pyrolysing the materials at temperatures (T) from 1000 to 1500 C. By modification of pre- and post-pyrolysis temperatures we obtained hard carbons with low surface areas, optimal carbonization degree and high electrochemical Na+ storage capacity in SIB halfcells. The best results were obtained when pre-pyrolysing peat at 450 C, washing out the impurities with KOH and HCl solutions and then post-pyrolysing the obtained carbon-rich material at 1400 C. All hard carbons were electrochemically characterized in half-cells (vs. Na/Na+) and capacities as high as 350 mA h g1 at 1.5 V and 250 mA h g1 in the plateau region (E < 0.2 V) were achieved at charging current density of 25 mA g1 with an initial coulombic efficiency of 80%.