On-site conversion reaction enables ion-conducting surface on red phosphorus/carbon anode for durable and fast sodium-ion batteries

The practical applications of high-capacity alloy-type anode materials in sodium-ion batteries(SIBs)are challenged by their vast volume effects and resulting unstable electrode-electrolyte interphases during discharge-charge cycling.Taking red phosphorus(P)/carbon anode material as an example,we report an on-site conversion reaction to intentionally eliminate the volume effect-dominated surface P and yield an ionically conducting layer of Na3PS4solid-state electrolyte on the composite.Such a surface reconstruction can significantly suppress the electrode swelling and simultaneously enable the activation energy of interfacial Na+transfer as low as 36.7 k J mol^(-1),resulting in excellent electrode stability and ultrafast reaction kinetics.Consequently,excellent cycling performance(510 mA h g^(-1)at 5 A g^(-1)after 1000 cycles with a tiny capacity fading rate of 0.016%per cycle)and outstanding rate capability(484 mA h g^(-1)at 10 A g^(-1)are achieved in half cells.When coupled with Na_(3)V_(2)(PO4)3cathode,the full cells exhibit 100%capacity retention over 200 cycles at 5C with an average Coulombic efficiency of 99.93%and a high energy density of 125.5 W h kg^(-1)at a power density of 8215.6 W kg^(-1)(charge or discharge within~49 s).Remarkably,the full cell can steadily operate at a high areal capacity of 1.9 mA h cm^(-2),the highest level among red P-based full SIBs ever reported.

EFFECT OF NITROGEN AND PHOSPHORUS ON THE GROWTH OF A RED TIDE DINOFLAGELLATE SCRIPPSIELLA TROCHOIDEA (STEIN) LOEBLICH III

Scrippsiella trochoidea (Stein) Loeblich III was grown in a nitrogen or phosphorus limited batch culture system in laboratory. Growth rates and cellular Chl a were measured as functions of nitrate and phosphate concentrations. Growth rates were hyperbolic with both nitrate and phosphate concentration and fit the Monod equation. The minimum cell quota of nitrogen and phosphorus and then the optimum N:P ratio of S. trochoidea were estimated in this study. Measurement of phosphate concentration in Jiaozhou Bay suggest that phosphorus is the limiting factor of S. trochoidea growth.

Response of Reactive Phosphorus Burial to the Sedimentary Transition from Cretaceous Black Shales to Oceanic Red Beds in Southern Tibet

The mechanism of sedimentary transition from the Cretaceous black shales to the oceanic red beds is a new and important direction of Cretaceous research. Chemical sequential extraction is applied to study the burial records of reactive phosphorus in the black shale of the Gyabula Formation and oceanic red beds of the Chuangde Formation, Southern Tibet. Results indicate that the principal reactive phosphorus species is the authigenic and carbonate-associated phosphorus （CAP） in the Gyabula Formation and iron oxides-associated phosphorus （FeP） in the Chuangde Formation which accounts for more than half of their own total phosphorus content. While the authigenic and carbonate-associated phosphorus （CAP） is almost equal in the two Formations; the iron oxidesassociated phosphorus is about 1.6 times higher in the Chuangde Formation than that in the Gyabula Formation resulting in a higher content of the total phosphorus in the Chuangde Formation. According to the observations on the marine phosphorus cyde in Modern Ocean, it is found that preferential burial and regeneration of reactive phosphorus corresponds to highly oxic and reducing conditions, respectively, leading to the different distribution of phosphorus in these two distinct type of marine sediments. It is the redox-sensitive behavior of phosphorus cycle to the different redox conditions in the ocean and the controlling effects of phosphorus to the marine production that stimulate the local sedimentary transition from the Cretaceous black shale to the oceanic red beds.

Influence of the concentration ratio of nitrogen to phosphorus on the growth and interspecies competition of two red tide algae

The growth and interspecies competition of two red tide algal species Thalassiosira pseudonana Hasle et Heimdal and Gymnodinium sp. were studied under different concentration ratios of nitrogen to phosphorus, and the algal hatch culture experiments were conducted. The physiological and biochemical indexes were measured periodically, including the maximum comparing growth rate, relative growth rate, average double time and chlorophyll a concentration. The results showed that when the concentration ratio of nitrogen to phosphorus was 16： 1, the maximum comparing growth rate, relative growth rate and chlorophyll a concentration of Thalassiosira pseudonana all reached the highest,and average double time was the shortest. This implied that the optimal concentration ratio of nitrogen to phosphorus of Thalassiosira pseudonana is 16： 1. When the concentration ratio of nitrogen to phosphorus was 6：1, the maximum comparing growth rate, relative growth rate and the chlorophyll a concentration of Gymnodinium sp. reached the highest, and average double time was the shortest, so the optimal concentration ratio of nitrogen to phosphorus of Gymnodinium sp. is 6： 1. From the growth curves as indicated both in the cell density and the chlorophyll a concentration, it is suggested that the influence of concentration ratio of nitrogen to phosphorus on the chlorophyll a concentration and the cell density are almost the same. Different concentration ratios of nitrogen to phosphorus had weak influence on community succession and the competition between the two algae. Gymnodinium sp. may use the phosphorus in vivo for growth, so it is important to pay attention to the concealment of phosphorus, in order to avoid the outbreak of red tide. On the basis of the importance of nitrogen and phosphorus and the ratio of their concentration, the possible outbreak mechanism of red tide of the two algae was also discussed.

Newly Design Porous/Sponge Red Phosphorus@Graphene and Highly Conductive Ni2P Electrode for Asymmetric Solid State Supercapacitive Device With Excellent Performance

Supercapacitors have attracted much attention in the field of electrochemical energy storage.However,material preparation,stability,performance as well as power density limit their applications in many fields.Herein,a sponge-like red phosphorus@graphene(rP@rGO)negative electrode and a Ni2P positive electrode were prepared using a simple one-step method.Both electrodes showed excellent performances(294 F g^−1 and 1526.6 F g^−1 for rP@rGO and Ni2P,respectively),which seem to be the highest among all rP@rGO-and Ni2P-based electrodes reported so far.The asymmetric solid-state supercapacitor was assembled by sandwiching a gel electrolyte-soaked cellulose paper between rP@rGO and Ni2P as the negative and positive electrodes.Compared to other asymmetric devices,the device,which attained a high operating window of up to 1.6 V,showed high energy and power density values of 41.66 and 1200 W kg−1,respectively.It also has an excellent cyclic stability up to 88%after various consecutive charge/discharge tests.Additionally,the device could power commercial light emitting diodes and fans for 30 s.So,the ease of the synthesis method and excellent performance of the prepared electrode materials mat have significant potential for energy storage applications.

Study on the Effect of Different Modified Zeolite to Phosphorus Activation in Red Soil

The activation of soil-fixed phosphorus is a long-term concern in soil science. In order to enhance the activation effect to soil-fixed phosphorus in red soil, different modified zeolite, through physical, chemical method and the associated both physics and chemistry, was used in this paper. The results showed as following: 1) the activated ability to soil-fixed phosphorus in red soil for modified zeolite was higher than the common one signally. Order of the ability for all kinds of modification zeolite in absolute activation amount and activation rate was: Modified in high temperature ammonium saturated zeolite > Ammonium saturated zeolite > Modified in high temperature zeolite > Common zeolite. 2) The increasing rate of modified phosphorus in high temperature ammonium saturated zeolite and ammonium saturated zeolite had a decline trend with time postponed while that for modified phosphorus in high temperature zeolite and routine zeolite was rising gradually with time postponed. For ammonium saturated zeolite, the increasing rate of phosphorus in low available phosphorus content red soil was significantly faster than that in red soil with the higher content of available phosphorus. 3) The activation rate for the same modified zeolite showed difference in different phosphorus level soil. The order is: SPhigh > SPmedium > SPlow.

A review on nanoconfinement engineering of red phosphorus for enhanced Li/Na/K-ion storage performances

Secondary batteries are widely used in energy storage equipment.To obtain high-performance batteries,the development and utilization of electrode materials with cheap price and ideal theoretical gravimetric and volumetric specific capacities have become particularly important.Naturally abundant and low-cost red phosphorus(RP)is recognized as an anode material with great promise because it has a theoretical capacity of 2596 mA h g^(-1) in lithium-ion batteries(LIBs)and sodium-ion batteries(SIBs).However,owing to the inferior discharging,the capacity of pure RP has a fast decay.Nanoconfinement of RP nanoparticles within porous carbon framework is one of the efficient methods to overcome these problems.In this review,we introduce the recent progress of RP confinement into carbon matrix as an energy storage anode material in LIBs,SIBs and potassium-ion batteries(PIBs).The synthetic strategies,lithiation/sodia tion/potassiation mechanism,and the electrochemical performances of RP/carbon composites(RP/C)with kinds of designed structures and P-C and P-O-C bond by kinds of methods are included.Finally,the challenges and perspectives of RP faced in the application development as anodes for LIBs/SIBs/PIBs are covered.This review will strengthen the understanding of composites of RP nanoparticles in porous carbon materials and aid researchers to carry out future work rationally.

Preparation,Characterization,and Performance of Lignin-based Microencapsulated Red Phosphorus Flame Retardant for ABS

The inherent difficulty in preservation and processing of conventional red phosphorus flame retardant severely limits its growing applications in polymer materials,thus,there is an urgent need to exploit effective technology to modify red phosphorus.Functionalized lignin-based compounds can provide a great potential in improving the preservation and processing of red phosphorus.Here,we prepared melamine modified lignin/aluminum phosphate coated red phosphorus(LMAP@RP)and used it as the flame retardant of acrylonitrile-butadiene-styrene(ABS)resin.With 25wt%loading LMAP@RP,the ABS samples show excellent flame inhibiting capacity and reached UL-94 V-0 rating.Cone calorimetry test results show that the peak heat release rate,total heat release and total smoke release of ABS/25LMAP@RP are reduced strikingly by 64.6%,49.3%,and 30.1%,respectively.The char residue is 15.36wt%and the char layer is continuous and dense.The outstanding flame retardant and smoke-suppressant performances of LMAP@RP show its application prospect for ABS.

Effect of Lanthanum on Nitrification, Phosphorus Transformation and Phenol Decomposition in Red Soil

The effect of La on nitrification, P transformation and phenol decomposition in red soil was studied by incubation and pot culture experiments. La at low concentration has stimulative effect on soil nitrification and P transformation while its high concentration has inhibitory effects, and the inhibition is strengthened with increasing concentration of La. La has strongly inhibitory effect on soil phenol decomposition and the inhibition is strengthened with increasing concentration of La. When the incubation time is prolonged, the inhibitory effect of La on soil nitrification and phenol decomposition tends to decrease.

Environmental Threshold of Phosphorus Infiltration in Red Soil under Different Land Use Patterns

The risk of soil phosphorus leaching increases in basin regions in light of large-scale use of phosphorus fertilizers because of agricultural modernization. In this study, we conducted an earth pillar simulation test on the infiltration threshold of red soil, Vaseline-coated PVC pipe, intact soil core, fine sand, and nylon filter was used for Penetration test, which covers the largest area of the Dianchi Lake Basin in China. Results showed that: 1) The contents of the total available phosphorus in algae (NaOH-P) and dissolved labile phosphorus (CaCl2-P) in red soil were consistent with the content of available phosphorus (Olsen-P) under different use patterns manifested by the law of greenhouse > open field > grassland. Grassland had the highest phosphorus sorption index (PSI), followed by the greenhouse and then by the open field. 2) The leachate under the same use pattern had the characteristics of total phosphorus (TP) > particle phosphorus (PP) > total dissolved phosphorus (TDP) > dissolved organic phosphorus (DOP) > molybdate reactive phosphorus (MRP). The TP contents in the leachates of grassland, greenhouse, and open field were 0.46, 0.61, and 0.49 mg/L, respectively. DOP, TDP, PP, and MRP had similar contents, and their distributions in the three land types were consistent with that of TP. 3) Olsen-P had a significant correlation with TP, TDP, PP, and DOP in the leachates. Olsen-P of <40 mg/kg and PSI of >50 slightly influenced eutrophication. Moreover, Olsen-P of >40 and <70.90 mg/kg and PSI of >40 had minimal influence on the environment. Olsen-P of >70.90 mg/kg and PSI of <30 significantly influenced eutrophication in Dianchi Lake Basin. 4) When Olsen-P was >26.09 mg/kg, the TP content in the leachate increased sharply.

Deciphering the potassium storage phase conversion mechanism of phosphorus by combined solid-state NMR spectroscopy and density functional theory calculations

Phosphorus is the potential anode material for emerging potassium-ion batteries(PIBs)owing to the highest specific capacity and relatively low operation plateau.However,the reversible delivered capacities of phosphorus-based anodes,in reality,are far from the theoretical capacity corresponding to the formation of K3P alloy.And,their underlying potassium storage mechanisms remain poorly understood.To address this issue,for the first time,we perform high-resolution solid-state31P NMR combined with XRD measurements,and density functional theory calculations to yield a systemic quantitative understanding of(de)potassiation reaction mechanism of phosphorus anode.We explicitly reveal a previously unknown asymmetrical nanocrystalline-to-amorphous transition process via rP←→(K_(3)P_(11),K_(3)P_(7),beta-K_(4)P_(6))←→(alpha-K4P6)←→(K_(1-x)P,KP,K_(4-x)P3,K_(1+x)P)←→(amorphous K4P3,amorphous K3P)that are proceed along with the electrochemical potassiation/depotassiation processes.Additionally,the corresponding KP alloys intermediates,such as the amorphous phases of K_(4)P_(3),K_(3)P,and the nonstoichiometric phases of“K_(1-x)P”,“K_(1+x)P”,“K_(4-x)P_(3)”are experimentally detected,which indicating various complicated K-P alloy species are coexisted and evolved with the sluggish electrochemical reaction kinetics,resulting in lower capacity of phosphorus-based anodes.Our findings offer some insights into the specific multi-phase evolution mechanism of alloying anodes that may be generally involved in conversion-type electrode materials for PIBs.

Optimizing Hydraulic and Chemical Properties of Iron and Aluminum Byproducts for Use in On-Farm Containment Structures for Phosphorus Removal

Phosphorus (P) transported in runoff from broiler production areas is a potential source for nutrient enrichment of local surface waters. Capturing nutrients prior to runoff leaving the production area could reduce the risk of transport. Commercially available systems for nitrogen (N) and P removal from stormwater are available but too expensive for widespread adoption on small, privately owned farms. The P adsorption capacities and hydraulic conductivities of locally-sourced iron red mud (RM) and aluminum water treatment residual (WT) were determined for potential on-farm treatment use. The byproducts were air-dried and separated into ≤2-, ≤6-, and ≤12.5-mm particle size fractions. Saturated hydraulic conductivity (HC) was determined for each particle-size fraction and results evaluated for the material’s ability to transmit a 25-year, 30-min rainfall of 6.6 cm. While the HC of ≤6-mm particles of each byproduct did not differ (p > 0.05;4.1 and 4.6 cm·min-1), for ≤12.5-mm particles it was greater (p > 0.05) for WT than RM (15.4 and 8.0 cm·min-1, respectively). However, all byproduct size fractions transmitted flow sufficiently to accommodate the baseline storm. Phosphorous adsorption maxima of ≤2-mm fraction for RM and WT were 25 and 10 g·P·kg-1, respectively. Using a solution containing 6 mg·P·L-1, rep-resenting the measured runoff-P concentration from areas adjacent to poultry house ventilation fans, the ≤2-mm fraction of RM removed 98% of added P and WT 84%. The ≤6-mm fraction of RM and WT removed 56% and 57% of added P, respectively, while the ≤12.5-mm fraction adsorbed only 28% and 10%. Results indicate the potential use of low-cost RM and WT byproducts to sequester P in runoff prior to P leaving poultry farm production areas.

Locally Sourced Iron and Aluminum Byproducts Decrease Phosphorus Leached from Broiler House Dust Deposited near Ventilation Fans

Freshwater impairment by eutrophication, as a result of excessive phosphorus (P) inputs from runoff in particular, remains a ubiquitous environmental concern. A common issue with systems designed to remove P and nitrogen (N) from runoff is their reduced effectiveness under high-flow conditions. To over-come this, P removal from broiler-house fan dust would be more effective if removal occurred at the nutrient source, where the water volume is limited to direct rainfall. The P removal efficiencies of different thicknesses of locally sourced, iron-rich red mud (RM) generated during the manufacture of steel belts for tires and alum-based drinking water treatment residual (WT) byproducts were investigated. Byproduct thicknesses of 4, 8, and 12 cm were tested using 57-L leaching columns. The columns were filled with the specified byproduct thickness and a 3-mm thickness of poultry house dust was surface applied prior to receiving six, 30-min simulated rainfalls (at 7 cm·hr-1) at 1-day intervals. The 8-cm thickness of both RM and WT outperformed the other thicknesses in terms of sorbing P released from the added broiler house dust, removing 99 and 96% of the added P, respectively, over the six simulated rainfall events. The 12-cm thickness of both RM and WT showed no additional benefit for P removal over the 8-cm thickness. As the 4-cm-thick WT treatment was less effective (89% of added P removed), the 8-cm thickness was the optimal thickness for field testing. Locally sourced materials with large P-sorbing capacities can offer a convenient, relatively inexpensive alternative for P removal from areas around poultry houses impacted by P-containing, exhausted broiler house dust.

Nutrient Removal Structures Using Locally-Sourced Iron and Aluminum By-Products Reduce Nutrient Runoff from Broiler Production Facilities

A common issue with filters designed to remove nutrients from runoff is their reduced effectiveness in high-flow conditions. To overcome this challenge, it was determined that nutrient removal from broiler-house fan dust could be more effective if nutrient removal was conducted at the nutrient source. The objective of this study was to evaluate the effectiveness of containment trays (CTs) holding locally sourced by-products installed adjacent to broiler house fans at the University of Arkansas Savoy broiler production facility to capture nutrients released from dust during rainfall over four years (2013 to 2017). By-products used were locally sourced, iron-based red mud (RM) generated during the manufacture of steel belts for tires and alum-based drinking water treatment residual (WTR), where both materials have large phosphorus (P) sorption capacities. Four-year mean annual concentrations of dissolved P of through-flow from RM CTs were consistently below 0.7 mg·L-1 and below 1.6 mg·L-1 for WTR CT through-flow. This equated to an average 11- and 4-fold decrease for RM and WTR, relative to concentrations in runoff from same-sized plots adjacent to sidewall fans, demonstrating their potential to trap P at the source and decrease P runoff to nearby flowing waters. While there was no significant decline in RM or WTR effective-ness over the four-year study, further work needs to be conducted to determine the lifespan of CTs. Use of RM and WTR in CTs at poultry broiler production facilities, along with their subsequent land application, has the potential to reduce the amount of by-product materials that are currently landfilled.

Influence of Azo Dye on Metabolism of Phosphorus Accumulating Organisms Linked to Transformation of Intracellular Storage Products

In this study, the influence of azo dye of methyl red (MR) on COD, dye and phosphorus removal and the transformation of polyhydroxyalkanoate (PHA) and glycogen of phosphate accumulating organisms in enhanced biological phosphorus removal (EBPR) system were investigated. The results indicated COD and dye removal efficiencies were decreased from 97.9% to 72.8% and 99.7% to 82.0%, respectively, when MR concentration was increased from 0 to 40 mg/L. Low MR concentration (5 mg/L) had no influence on P removal and transformation of PHA and glycogen. However, P removal, PHA production and consumption, and glycogen replenishment were seriously inhibited at high MR concentration, while glycogen hydrolysis was simulated at MR concentration of 20 and 40 mg/L. The transformations of PHA and glycogen at aerobic condition were more sensitive to those at anaerobic condition at high MR concentration. These results demonstrated dye and its intermediate products would inhibit the metabolism of polyphosphate accumulating organisms, which should be taken into account in future work.

High-yield red phosphorus sponge mediated robust lithium-sulfur battery

Although lithium-sulfur(Li-S)batteries with high specific energy exhibit great potential for next-generation energy-storage systems,their practical applications are limited by the growth of Li dendrites and lithium polysulfides(LiPSs)shuttling.Herein,a highly porous red phosphorus sponge(HPPS)with well distributed pore structure was efficiently prepared via a facile and largescale hydrothermal process for polysulfides adsorption and dendrite suppression.As experimental demonstrated,the porous red phosphorus modified separator with increased active site greatly promotes the chemisorption of LiPSs to efficiently immobilize the active sulfur within the cathode section,while Li metal anode activated by Li_(3)P interlayer with abundant ionically conductive channels significantly eliminates the barrier for uniform Li^(+)permeation across the interlayer,contributing to the enhanced stability for both S cathode and Li anode.Mediated by the HPPS,long-term stability of 1,200 h with minor voltage hysteresis is achieved in symmetric cells with Li_(3)P@Li electrode while Li-S half-cell based on HPPS modified separator delivers an outperformed reversibility of 783.0 mAh·g^(−1)after 300 cycles as well as high-rate performance of 694.5 mAh·g^(−1)at 3 C,which further boosts the HPPS tuned full cells in practical S loading(3 mg·cm^(−2))and thin Li3P@Li electrode(100μm)with a capacity retention of 71.8%after 200 cycles at 0.5 C.This work provides a cost-effective and metal free mediator for simultaneously alleviating the fundamental issues of both S cathode and Li anode towards high energy density and long cycle life Li-S full batteries.

A facile fabrication of novel stuff with antibacterial property and osteogenic promotion utilizing red phosphorus and near-infrared light

Bone-implant materials are important for bone repairing and orthopedics surgery,which include bone plates and bone nails.These materials need to be designed not only considering its biostability and biocompatibility,but also their by-products induced infection after therapy or long-time treatment in vivo.Thus,the development of novel implant materials is quite urgent.Red phosphorus has great biocompatibility and exhibits efficient photothermal ability.Herein,a red phosphorus/IR780/arginine-glycine-asparticacid-cysteine(RGDC)coating on titanium bone-implant was prepared.The temperature sensitivity of Staphylococcus aureus biofilm is enhanced in the presence of ROS produced by IR780 with 808 nm light irradiation.With keeping the cells and tissues normal,a high antibacterial performance can be realized by near-infrared(808 nm)irradiated within 10 min at 50℃.Besides the high effective antibacterial efficacy provided by photothermal therapy(PTT)and photodynamic therapy(PDT),the RGDC decorated surface can also possess an excellent performance in osteogenesis in vivo.

Hierarchical red phosphorus incorporated TiO_(2) hollow sphere heterojunctions toward superior photocatalytic hydrogen production

Solar-to-hydrogen conversion through photocatalysis is a sustainable and promising strategy for storing solar energy.Recently,elemental red phosphorus(RP)with broad light absorption has been recognized as a potential candidate for photocatalytic hydrogen evolution,while challenges remain due to the rapid recombination of photogenerated carriers.In this work,RP modified TiO_(2)hollow spheres were designed and fabricated through the chemical vapor deposition method.The optimal hydrogen production rate reaching 215.5μmol/(g h)over TiO_(2)@RP heterostructure was obtained under simulated solar light irradiation.Experimental results evidenced that the hollow sphere structure and RP light absorber extended light absorption ability,and the heterostructure induced interfacial charge migration facilitated photoinduced charge separation,which benefited the photocatalytic hydrogen production performance.

A novel battery scheme:Coupling nanostructured phosphorus anodes with lithium sulfide cathodes

Lithium-ion batteries are approaching their theoretical limit and can no longer keep up with the increasing demands of human society.Lithium-sulfur batteries,with a high theoretical specific energy,are promising candidates for next generation energy storage.However,the use of Li metal in Li-S batteries compromises both safety and performance,enabling dendrite formation and causing fast capacity degradation.Previous studies have probed alternative battery systems to replace the metallic Li in Li-S system,such as a Si/Li2S couple,with limited success in performance.Recently,there is a focus on red P as a favorable anode material to host Li.Here,we establish a novel battery scheme by utilizing a P/C nanocomposite anode and pairing it with a Li2S coated carbon nanofiber cathode.We find that red P anode can be compatible in ether-based electrolyte systems and can be successfully coupled to a Li2S cathode.Our proof of concept full-cell displays remarkable specific capacity,rate and cycling performances.We expect our work will provide a useful alternative system and valuable insight in the quest for next generation energy storage devices.

Single-step flash-heat synthesis of red phosphorus/ graphene flame-retardant composite as flexible anodes for sodium-ion batteries

Red phosphorus （RP） has attracted considerable attention as the anode for high-performance Na-ion batteries, owing to its low cost and high theoretical specific capacity of -2,600 mAh/g. In this study, a facile single-step flash-heat treatment was developed to achieve the reduction of graphene oxide （GO） and the simultaneous deposition of RP onto the reduced graphene oxide （rGO） sheets. The resulting RP/rGO composite was shown to be a promising candidate for overcoming the issues associated with the poor electronic conductivity and large volume variation of RP during cycling. The RP/rGO flexible film anode delivered an average capacity of 1,625 mAh/g during 200 cycles at a charge/ discharge current density of 1 A/g. Average charge capacities of 1,786, 1,597, 1,324, and 679 mAh/g at 1, 2, 4, and 6 A/g current densities were obtained in the rate capability tests. Moreover, owing to the RP component, the RP/rGO film presented superior flame retardancy compared to an rGO film. This work thus introduces a highly accessible synthesis method to prepare flexible and safe RP anodes with superior electrochemical performance toward Na-ion storage.