title: Carbon nanosheet frameworks derived from peat moss as high performance sodium ion battery anodes.
abstract: We demonstrate that peat moss, a wild plant that covers 3% of the earth's surface, serves as an ideal precursor to create sodium ion battery (NIB) anodes with some of the most attractive electrochemical properties ever reported for carbonaceous materials. By inheriting the unique cellular structure of peat moss leaves, the resultant materials are composed of three-dimensional macroporous interconnected networks of carbon nanosheets (as thin as 60 nm). The peat moss tissue is highly cross-linked, being rich in lignin and hemicellulose, suppressing the nucleation of equilibrium graphite even at 1100 °C. Rather, the carbons form highly ordered pseudographitic arrays with substantially larger intergraphene spacing (0.388 nm) than graphite (c/2 = 0.3354 nm). XRD analysis demonstrates that this allows for significant Na intercalation to occur even below 0.2 V vs Na/Na(+). By also incorporating a mild (300 °C) air activation step, we introduce hierarchical micro- and mesoporosity that tremendously improves the high rate performance through facile electrolyte access and further reduced Na ion diffusion distances. The optimized structures (carbonization at 1100 °C + activation) result in a stable cycling capacity of 298 mAh g(-1) (after 10 cycles, 50 mA g(-1)), with ∼150 mAh g(-1) of charge accumulating between 0.1 and 0.001 V with negligible voltage hysteresis in that region, nearly 100% cycling Coulombic efficiency, and superb cycling retention and high rate capacity (255 mAh g(-1) at the 210th cycle, stable capacity of 203 mAh g(-1) at 500 mA g(-1)).
authors.affiliation: Chemical and Materials Engineering, University of Alberta , Edmonton, Alberta T6G 2V4, Canada.
authors.forename: Jia
authors.initials: J
authors.lastname: Ding
authors.forename: Huanlei
authors.initials: H
authors.lastname: Wang
authors.forename: Zhi
authors.initials: Z
authors.lastname: Li
authors.forename: Alireza
authors.initials: A
authors.lastname: Kohandehghan
authors.forename: Kai
authors.initials: K
authors.lastname: Cui
authors.forename: Zhanwei
authors.initials: Z
authors.lastname: Xu
authors.forename: Beniamin
authors.initials: B
authors.lastname: Zahiri
authors.forename: Xuehai
authors.initials: X
authors.lastname: Tan
authors.forename: Elmira Memarzadeh
authors.initials: EM
authors.lastname: Lotfabad
authors.forename: Brian C
authors.initials: BC
authors.lastname: Olsen
authors.forename: David
authors.initials: D
authors.lastname: Mitlin
mesh_terms: D001674:Bioelectric Energy Sources; D018533:Biomass; D002244:Carbon / Q000737:chemistry; D004058:Diffusion; D004563:Electrochemistry; D004566:Electrodes; D004573:Electrolytes; D006108:Graphite / Q000737:chemistry; D007477:Ions; D008094:Lithium / Q000737:chemistry; D036103:Nanotechnology; D037742:Nanotubes, Carbon / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D012964:Sodium / Q000737:chemistry*; D012987:Soil; D044003:Sphagnopsida / Q000737:chemistry / Q000166:cytology; D013499:Surface Properties; D013696:Temperature
chemical_list: D004573:Electrolytes; D007477:Ions; D037742:Nanotubes, Carbon; D011108:Polymers; D012987:Soil; D002244:Carbon; D006108:Graphite; D008094:Lithium; D012964:Sodium