Achieving high initial Coulombic efficiency for competent Na storage by microstructure tailoring from chiral nematic nanocrystalline cellulose

Abstract

Although it has been proven that porous, heteroatomic, and defective structures improve Na storage performance, they also severely affect the initial Coulombic efficiency (ICE) due to the huge irreversible capacity in the first cycle, which always limits the practical application of carbon anodes in commercial Na-ion batteries (NIBs). Here, we show the successful synthesis of nanocrystalline cellulose and the derivative hard carbons. A series of treatments including acid hydrolysis, hydrothermal carbonization, and hightemperature pyrolysis help tune the pores, heteroatoms, and defects to achieve an optimized balance between superior ICE and reversible capacity of up to 90.4% and 314 mAh g −1 . This study highlights that tailoring the electrode microstructure could be an important strategy in the future design of carbonaceous anode materials for high-performance Na-ion batteries.

Nanocellulosics in Transient Technology

“…When paired with Na 2 Fe 2 (SO 4 ) 3 cathode, the fabricated battery attained an energy density of 240 Wh kg –1 , and delivered up to 69.7 mAh g –1 after 50 cycles @ rate of 1 C. Thus, opening the opportunity for ecofriendly and economically sustainable rechargeable batteries from sodium . In a related report, it has been established that a relationship exist between microstructural characteristics of materials and the electrochemical performance in batteries . Native cellulose treated with sulfuric acid was converted into chiral nematic nanocrystalline cellulose (NCC); subsequently, by employing a combination of acid hydrolysis, hydrothermal carbonization, and high temperature pyrolysis, tailored carbon microstructures for efficient NIB electrodes were successfully fabricated .…”

“…116 However, it was noted that further research is needed toward the quantification of the specific relationship between parameters (for example, pore/heteroatoms/defects and electrochemical performance), with relation to ICE of the carbon anodes toward optimizing the anodic output for higher efficiencies. 116 In another development, to boost the storage energy densities and to mitigate the challenge of low specific capacities of existing commercial anodic materials (for example, graphitic and titanate) employed in LIBs toward next-generation rechargeable energy systems, a vacuum-assisted filtration technique was used to fabricate free-standing, flexible anode composed of black phosphorus (BP) nanosheets and nanocellulose (NC) nanowires (BP@NC), as demonstrated in Figure 11. 117 BP is gaining interests as promising anodic material for constructing flexible high-energy-density LIBs.…”

“…The obtained carbon exhibited an exceptional initial Coulombic efficiency (ICE) of 90.4% with an outstanding reversible capacity of 314 mAh g –1 @ 0.1 C; thereby demonstrating the potential and performance possibilities of NIBs . However, it was noted that further research is needed toward the quantification of the specific relationship between parameters (for example, pore/heteroatoms/defects and electrochemical performance), with relation to ICE of the carbon anodes toward optimizing the anodic output for higher efficiencies …”

“… 115 In a related report, it has been established that a relationship exist between microstructural characteristics of materials and the electrochemical performance in batteries. 116 Native cellulose treated with sulfuric acid was converted into chiral nematic nanocrystalline cellulose (NCC); subsequently, by employing a combination of acid hydrolysis, hydrothermal carbonization, and high temperature pyrolysis, tailored carbon microstructures for efficient NIB electrodes were successfully fabricated. 116 The obtained carbon exhibited an exceptional initial Coulombic efficiency (ICE) of 90.4% with an outstanding reversible capacity of 314 mAh g –1 @ 0.1 C; thereby demonstrating the potential and performance possibilities of NIBs.…”

“… 116 Native cellulose treated with sulfuric acid was converted into chiral nematic nanocrystalline cellulose (NCC); subsequently, by employing a combination of acid hydrolysis, hydrothermal carbonization, and high temperature pyrolysis, tailored carbon microstructures for efficient NIB electrodes were successfully fabricated. 116 The obtained carbon exhibited an exceptional initial Coulombic efficiency (ICE) of 90.4% with an outstanding reversible capacity of 314 mAh g –1 @ 0.1 C; thereby demonstrating the potential and performance possibilities of NIBs. 116 However, it was noted that further research is needed toward the quantification of the specific relationship between parameters (for example, pore/heteroatoms/defects and electrochemical performance), with relation to ICE of the carbon anodes toward optimizing the anodic output for higher efficiencies.…”