Ultrahigh Rate Capability Research Articles

In Situ Electrochemically Oxidative Activation Inducing Ultrahigh Rate Capability of Vanadium Oxynitride/Carbon Cathode for Zinc-Ion Batteries.

As a promising candidate for large-scale energy storage, aqueous zinc-ion batteries (ZIBs) still lack cathode materials with large capacity and high rate capability. Herein, a spherical carbon-confined nanovanadium oxynitride with a polycrystalline feature (VNxOy/C) was synthesized by the solvothermal reaction and following nitridation treatment. As a cathode material for ZIBs, it is interesting that the electrochemical performance of the VNxOy/C cathode is greatly improved after the first charging process viain situ electrochemically oxidative activation. The oxidized VNxOy/C delivers a greatly enhanced reversible capacity of 556 mAh g-1 at 0.2 A g-1 compared to the first discharge capacity of 130 mAh g-1 and a high capacity of 168 mAh g-1 even at 80 A g-1. The ex situ characterizations verify that the insertion/extraction of Zn2+ does not affect the crystal structure of oxidized VNxOy/C to promise a stable cycle life (retain 420 mAh g-1 after 1000 cycles at 10 A g-1). The experimental analysis further elucidates that charging voltage and H2O in the electrolyte are curial factors to activate VNxOy/C in that the oxygen replaces the partial nitrogen and creates abundant vacancies, inducing a conversion from VNxOy/C to VNx-mOy+2m/C and then resulting in considerably strengthened rate performance and improved Zn2+ storage capability. The study broadens the horizons of fast ion transport and is exceptionally desirable to expedite the application of high-rate ZIBs.

Ultra-high rate capability of in-situ anchoring FeF3 cathode onto double-enhanced conductive Fe/graphitic carbon for high energy density lithium-ion batteries

The FeF3 cathode shows some promising potentials for lithium-ion batteries (LIBs) because of its high theoretical capacity induced by conversion reactions, but the poor electrical conductivity and inferior reaction kinetics severely limit battery performance. Herein, the FeF3 nanoparticles embedded in double Fe/graphitized carbon (GC) matrices (FeF3/Fe/GC) are fabricated using low-temperature fluorination, where the spongy structure originates from the unique self-expanding process. It was found that the pseudocapacitive contribution of the optimized FeF3/Fe/GC nanocomposite is as high as 98%, which contributes to a high specific capacity of 151.2 mA h g−1 at a high rate of 10 C after 1000 cycles, with a capacity decay rate of only 0.03% per cycle. Surprisingly, even at an ultra-high rate of 100 C, the composite cathode still delivers a discharge capacity as high as 106.7 mA h g−1, which is superior to those reported in the previous studies. The excellent cycle stability and ultra-high rate performance can be attributed to the intimate contact between double Fe/GC matrices and ultrafine FeF3 nanoparticles, which can effectively reduce the diffusion barrier of ions and electrons to enhance the redox pseudocapacitive process. It has been demonstrated that optimizing the pseudocapacitive behavior may be a simple yet effective strategy to obtain the cathode materials with ultra-high rate capability.

Hybrid nanotubes constructed by confining Ti0.95Nb0.95O4 quantum dots in porous bamboo-like CNTs: superior anode materials for boosting lithium storage.

Current commercial lithium ion battery (LIB) anodes comprising graphite and Li4Ti5O12 inevitably suffer from safety risk and low energy density. Hence, a novel anode material of Ti0.95Nb0.95O4/C hybrid nanotubes was developed via a modified sol-gel method combined with subsequent calcination. The hybrids consist of Ti0.95Nb0.95O4 quantum dots that are homogeneously embedded in the walls of porous bamboo-like CNTs. The high capacity feature of multiple redox couples of Ti-Nb-O based anodes is demonstrated by ex situ XPS in the hybrids. With the advantages of stimulative lithium storage, increased conductivity and robust mechanical properties due to the unique hybrid structure, the hybrids exhibit a high capacity (516.8 mA h g-1 at 0.2 A g-1), superior long-term cycling stability (142.7 mA h g-1 at 5 A g-1 after 3000 cycles) and an ultra-high rate capability (234.6 mA h g-1 at 1 A g-1 and 125 mA h g-1 at 8 A g-1). Meanwhile, the hybrids showed superior electrochemical performance compared with the reported Li4Ti5O12 and Ti-Nb-O based anodes. Furthermore, the GITT measurements revealed the fast Li+ transport for the charge-discharge processes of the hybrids. Such prominent merits of the Ti0.95Nb0.95O4/C hybrid nanotubes make them more likely candidates that can replace graphite and Li4Ti5O12 anodes in LIBs.

Constructing Ni–Co PBA derived 3D/1D/2D NiO/NiCo2O4/NiMn-LDH hierarchical heterostructures for ultrahigh rate capability in hybrid supercapacitors

Engineering hierarchical heterostructure materials has been recognised as a challenging but prepossessing strategy for developing hybrid supercapacitors.

Oxygen vacancy-modulated zeolitic Li4Ti5O12 microsphere anode for superior lithium-ion battery

Spinel Li4Ti5O12 (LTO) is a promising anode material for state-of-the-art high-power lithium-ion batteries (LIBs) owing to its “zero strain” characteristics during fast charging/discharging, long cycle life, and high rate capability. However, the poor ionic/electronic conductivity and sluggish ionic diffusion coefficient of LTO restrict its practical utility. Porous zeolitic LTO (Z-LTO) microspheres were synthesized herein as anode materials for LIBs using TiO2 and LiOH∙H2O via a hydrothermal method combined with Ar/H2 thermal treatment. The increased concentration of Ti3+ self-doping-derived oxygen vacancies in as-synthesized Z-LTO and porous microspherical Z-LTO aggregates greatly improved the electronic conductivity and structural stability. These features contributed to achieving much higher discharge capacities of ∼210 and ∼180 mAh g−1 at 0.5 C and 1 C rates, respectively, as well as excellent ultra-high rate capability of 45 mAh g–1 at 50 C rate, while still maintaining the outstanding long-life cyclic stability (∼181 mAh g−1 at 5 C rate after 2000 cycles), with 90% capacity retention, compared to commercial LTO (C-LTO). Charge contribution kinetics analysis indicated that the lithium storage mechanisms in Z-LTO, particularly at a high rate, were dominantly diffusion-controlled due to the larger ion-diffusion ability (DLi ≈ 4.18 × 10−8 cm2 s−1). This finding confirms that the generation of surface defects by creating Ti3+/Ti4+ pairs and oxygen vacancy engineering in LTO is an effective approach for enhancing the ion/electron mobility, which can be extended to boost the battery performance of other materials with low ionic conductivities for advanced energy storage systems.

Constructing Carbon Nanotube Hybrid Fiber Electrodes with Unique Hierarchical Microcrack Structure for High-Voltage, Ultrahigh-Rate, and Ultralong-Life Flexible Aqueous Zinc Batteries.

Flexible aqueous zinc batteries are promising candidates as safe power sources for fast-growing portable and wearable electronics. However, the low working voltage, poor rate capability, and cycling stability have greatly restricted their development and applications. Here, a new family of flexible bimetallic phosphide/carbon nanotube hybrid fiber electrodes with unique macroscopic microcrack structure and microscopic porous nanoflower structure is reported. The hierarchical microcrack structure not only facilitates the penetration of electrolyte for effective exposure of active sites, but also can serve as buffers to relieve the stress concentrations of the fiber electrode under deformations, enabling impressive electrochemical performance and mechanical flexibility. Particularly, the fabricated flexible aqueous zinc batteries demonstrate high working voltage plateau and specific capacity (≈1.7V, 258.9 mAh g-1 at 2 A g-1 ), ultrahigh rate capability (135.8 mAh g-1 at 50 A g-1 , fully charged in only 9.8 s) and impressive power density of 79 000W kg-1 . Moreover, the flexible batteries show ultralong cycling life with 74.6% capacity retention after 20 000 cycles. The fiber batteries are also highly flexible and can be easily knitted into soft electronic textiles to power a smartphone, which are particularly promising for the next-generation of flexible and wearable electronics.

Cooperative stabilization by highly efficient nanoseeds and reinforced interphase toward practical Li metal batteries

The practical implementation of Li metal has been severely obstructed by the uncontrolled dendritic Li growth and poor cycling efficiency. Herein, highly lithiophilic, ultrathin (∼60 nm) and conformal bismuth-oxygen-carbon layer-modified carbon fibers (CF@BOC) first prepared from the bismuth-based MOF membrane self-assembly were rationally adopted to stabilize Li metal. Highly efficient ultrasmall (∼1.8 nm) bismuth seeds and in-situ generated Li2O-enriched interphase can cooperatively enable the homogeneous Li nucleation/growth and extraordinarily high Li utilization efficiency. Consequently, the modified Li metal exhibits ultrahigh rate capability (10 mA cm−2) and ultralong lifespan stability (6900 cycles). Impressively, the Li|LiFePO4 full cell delivers an exceptional long-term cycling over 200 cycles under the rather harsh condition of low negative-to-positive-capacity (N/P) ratio (∼0.44) and electrolyte-to-capacity (E/C) ratio (5 g Ah−1). And the Li|LiCoO2 full cell also reveals a prolonged cycling performance even at the ultralow N/P ratio (∼0.26) with a remarkable energy density of 361.3 Wh kg−1. Furthermore, the pouch cell with a high loading cathode (3.6 mAh cm−2) still demonstrates prolonged cycling lifespan under the practical condition of extremely limited Li metal and lean electrolyte. This work enlightens a significant stride toward highly stable Li metal anode for practicability.

Amorphous Ni–Co binary hydroxide with super-long cycle life and ultrahigh rate capability as asymmetric supercapacitors

Ni–Co binary hydroxide (Ni x Co1−x (OH)2) with nanostructure is prepared by one-step electrochemical deposition process with de-ionized water as electrolyte. The molar ratio of Ni/Co for Ni x Co1−x (OH)2 can be accurately controlled via changing the composition of the alloy target. A series of typical hydroxides are synthesized with Ni/Co molar ratios of 1:2, 1:3, 1:4, 1:6, 6:1, 4:1, 3:1, 2:1 and 1:1. The electrochemical performances of Ni x Co1−x (OH)2 exhibit remarkable improvement in rate capability and cycling stability compared to monometallic hydroxide. Electrochemical test results reveal that Ni4/5Co1/5(OH)2 delivers the maximum specific capacitance of 2425 F g−1, while Ni0.5Co0.5(OH)2 exhibits ultrahigh rate capability (a 14% capacity decrease after a 100-fold increase in scan rate and 7% capacity decrease after a 40-fold increase in current density) and super-long cycle life (no capacitance loss after 50 000 cycles). Especially, the Ni0.5Co0.5(OH)2//AC supercapacitor exhibits a super-long cycle life with a 2% capacitance loss after 100 000 cycles, which is quite better than that of crystalline devices.

Mn2+/I- Hybrid Cathode with Superior Conversion Efficiency for Ultrahigh-Areal-Capacity Aqueous Zinc Batteries.

Aqueous Zn-Mn2+ electrolysis batteries utilizing the two-electron-transfer reaction between Mn2+ and MnO2 attract great attention because of their superior theoretical capacity (616 mAh g-1). However, the low conductivity of deposited MnO2 and the poor conversion efficiency of Mn2+/MnO2 inevitably result in limited areal capacity and unsatisfied cycling stability, which have become the main hurdles of aqueous Zn-Mn2+ batteries' applications. Herein, we propose a novel Mn2+/I- hybrid cathode that couples the triiodide/iodide redox with the Mn2+/MnO2 redox to optimize the electrolysis kinetics. Because of the synergistically enhanced conversion reaction between Mn2+/I- and the promoter effect of I- to the dissolution of MnO2, this hybrid cathode not only exhibits fast reaction kinetics, thus demonstrating ultrahigh rate capability (100 mA cm-2), but also displays observably enhanced conversion efficiency up to 96.0% with excellent reversibility of 2000 cycles. Especially the superhigh areal capacity of 20 mAh cm-2 with more than 100 cycles among the reported static Zn-Mn2+ electrolysis batteries is demonstrated. The excellent battery performance as well as the facile electrode hybridization approach designed here paves the way for the practical applications of aqueous Zn batteries.

Design and Synthesis of a π‐Conjugated N‐Heteroaromatic Material for Aqueous Zinc–Organic Batteries with Ultrahigh Rate and Extremely Long Life

Electroactive organic materials with tailored functional groups are of great importance for aqueous Zn-organic batteries due to their green and renewable nature. Herein, a completely new N-heteroaromatic material, hexaazatrinaphthalene-phenazine (HATN-PNZ) is designed and synthesized, by an acid-catalyzed condensation reaction, and its use as an ultrahigh performance cathode for Zn-ion batteries demonstrated. Compared with phenazine monomer, it is revealed that the π-conjugated structure of N-heteroaromatics can effectively increase electron delocalization, thereby improving its electrical conductivity. Furthermore, the enlarged aromatic structure noticeably suppresses its dissolution in aqueous electrolytes, thus enabling high structural stability. As expected, the HATN-PNZ cathode delivers a large reversible capacity of 257mAhg-1 at 5Ag-1 , ultrahigh rate capability of 144mAhg-1 at 100Ag-1 , and an extremely long cycle life of 45000 cycles at 50Ag-1 . Investigation of the charge-storage mechanism demonstrates the synergistic coordination of both Zn2+ and H+ cations with the phenanthroline groups, with Zn2+ first followed by H+ , accompanying the reversible formation of zinc hydroxide sulfate hydrate. This work provides a molecular-engineering strategy for superior organic materials and adds new insights to understand the charge-storage behavior of aqueous Zn-organic batteries.

Rational design of 3D porous niobium carbide MXene/rGO hybrid aerogels as promising anode for potassium-ion batteries with ultrahigh rate capability

Rational design of 3D porous niobium carbide MXene/rGO hybrid aerogels as promising anode for potassium-ion batteries with ultrahigh rate capability

Ultrahigh rate capability of manganese based olivine cathodes enabled by interfacial electron transport enhancement

Manganese-based Olivine is a promising cathode candidate with high energy and low cost for Li-ion batteries (LIBs). Its rate capability and cyclability challenges still remain even with nano-size and carbon coating. Herein, an ultrahigh rate performance is achieved by introducing an affinitive conductor to enhance the interfacial electron transport of LiMn0.7Fe0.3PO4via Li3V2(PO4)3. It is found that the Li3V2(PO4)3 facilitates sp2 hybridization to form a highly conductive carbon coating during the carbonized process. The composite 0.9LiMn0.7Fe0.3PO4·0.1Li3V2(PO4)3 can deliver a capacity of 90.9 mAh g−1 and power density of 11444 W kg−1 at 50 C-rate. Both in situ X-ray diffraction and conductive-atomic force microscopy are conducted to understand the synergetic effect between LiMn0.7Fe0.3PO4 and Li3V2(PO4)3. The results suggest that the interfacial electron transfer between LiMn0.7Fe0.3PO4 particles and the electron conducting medium, such as binder/carbon black composite, is greatly improved so that the highly Li+ conductive nature of olivine materials can be fully unleashed. This work demonstrates the importance of efficient interfacial electron transfer to the active cathode particles, and opens up a new venue for the rational design of high-energy and high-power batteries.

In2S3 nanosheets array anchored on reduced graphene oxide as high-performance anode for sodium-ion batteries

Indium sulfide has been proved to be a high-capacity anode material for sodium-ion batteries, but severe volume changes and low electrical conductivity limit its practical electrochemical performance. Based on this, graphene (RGO)-loaded In 2 S 3 nanosheets array composites (In 2 S 3 /RGO) are synthesized by a simple reflux method to enhance charge transfer and ion diffusion kinetics as well as the structural stability of electrodes. By optimizing the amount of RGO, In 2 S 3 /RGO exhibits a high specific capacity of 450 mAh g −1 at 2 A g −1 after 500 cycles with a capacity fading of 0.04% per cycle (from 2nd to 500th) and remarkable rate performance of 460 mAh g −1 at 12 A g −1 . The XRD and HRTEM analysis indicates that In 2 S 3 /RGO is based on a conversion mechanism for energy storage. Furthermore, the In 2 S 3 /RGO//Na 3 V 2 (PO 4 ) 3 full cell is successfully fabricated. The simple and efficient synthesis method and the excellent sodium storage properties offer great prospects for the practical application of In 2 S 3 /RGO. The graphene (RGO)-modified In 2 S 3 nanosheet array composites (In 2 S 3 /RGO) are first synthesized for SIBs. It shows excellent rate capability (758.2 mAh g −1 at 0.5 A g −1 and 460 mAh g −1 even at 12 A g −1 ) and cycle stability (450 mAh g −1 at 2 A g −1 after 500 cycles) for Na + storage. And ex-situ XRD and HRTEM results revealed that In 2 S 3 /RGO is based on a conversion mechanism for Na-ion storage. • In situ growth of In 2 S 3 nanosheet arrays on RGO was achieved by a simple reflux method. • The In 2 S 3 /RGO composite exhibits ultratable cycling performance and ultrahigh rate capability. • The redox reactions are dominated by pseudocapacitive behavior. • Revealed the energy storage mechanism of In 2 S 3 /RGO by ex-situ XRD patterns and HRTEM images.

Heterostructure of MnCo2O4 intercalated graphene oxide coated with Ni-V-Se nanoparticles for supercapacitors with high rate capability

A new approach was proposed to construct a novel 3D hybrid nanocomposite heterostructure GO/MnCo2O4/Ni-V-Se as a hybrid supercapacitor electrode. Electrons can easily migrate from Mn ions to Ni ions, thereby increasing the electron energy of the metal orbital, and this inductive effect can effectively improve the electron transfer efficiency. In addition, the application of surface/interface control method also enables this electrode material to exhibit unique advantages. In this heterostructure, graphene serves as the extended conductive framework, cube-like MnCo2O4 and flower-like Ni-V-Se spheres derived from MOFs as spacers separate the sheets to avoid the layer-by-layer stacking of graphene. Complemented by Ni-V-Se coating, the formed composite heterostructure exhibits excellent electrochemical performance. The as-prepared GO/MnCo2O4/Ni-V-Se delivers ultra-high specific capacity (1292.3 C·g−1 at 1 A·g−1), rate capability (94.87%) and cycling stability. Finally, the hybrid supercapacitor assembled by GO/MnCo2O4/Ni-V-Se and activated carbon also shows good electrochemical performance.

Revealing bulk reaction kinetics of battery-like electrode for pseudocapacitor with ultra-high rate performance

Battery-like electrode materials have a high theoretical capacity but suffer from low electrical conductivity and poor structural stability, which are expected to be solved by revealing bulk reaction kinetics of crystal structure to improve the electrochemical performance. Herein, we grow NiCo-LDH single-crystal nanowires along the [003] crystal plane on the surface of amorphous SiO2 hollow spheres. This heterostructured architecture provides a synergistic effect among different components and enlarges the interlayer spacing of the grown NiCo-LDH single-crystal, offering more reactive sites and improving electrical conductivity. The prepared NiCo-LDH@SiO2/C electrode demonstrates ultra-high rate capability with 78.1 % capacitance retention even after a 40-fold increase in the current density. The asymmetric supercapacitors with NiCo-LDH@SiO2/C cathode and active carbon anode could deliver a maximum energy density of 47.6 Wh/g at 1383 W/kg. This work presents a new method to guide the design of NiCo-LDH electrode materials and opens up a new opportunity to develop high-performance battery-type electrode materials for pseudocapacitors.

Oxygen vacancies enriched Bi2O3 as high capacity and high rate negative material for aqueous alkali battery

Aqueous alkaline batteries (AABs) represent a prospective category of rechargeable energy devices that can ensure both high energy and power densities. The high capacity negative material is urgently needed to match with the positive electrode and maximize the overall charge storage ability of AAB. Herein, an oxygen vacancies (Ov) enriched Bi2O3 was prepared as efficient negative material for AAB via solvothermal hydrolysis of Bi salt and calcination in inert atmosphere. The resultant Bi2O3 electrode demonstrated high specific capacity (Cs) of 249 mAh g−1 at 1 A g−1 and ultrahigh rate capability (230 mAh g−1 at 10 A g−1) in a wide negative potential range, which was higher than those of other battery materials. When paired with Co, Ni layered double hydroxide (CoNi-LDH) positive electrode, the AAB based on the Bi2O3 negative electrode delivered high energy density (Ecell, 87.1 Wh kg−1 at power density (Pcell) of 1037 W kg−1) and good durability, manifesting the potential of Ov enriched Bi2O3 in battery typed charge storage.

Na1.51 Fe[Fe(CN)6 ]0.87 ·1.83H2 O Hollow Nanospheres via Non-Aqueous Ball-Milling Route to Achieve High Initial Coulombic Efficiency and High Rate Capability in Sodium-Ion Batteries.

Prussian blue analogues (PBAs) have attracted extensive attention as cathode materials in sodium-ion batteries (SIBs) due to their low cost, high theoretical capacity, and facile synthesis process. However, it is of great challenge to control the crystal vacancies and interstitial water formed during the aqueous co-precipitation method, which are also the key factors in determining the electrochemical performance. Herein, an antioxidant and chelating agent co-assisted non-aqueous ball-milling method to generate highly-crystallized Na2- x Fe[Fe(CN)6 ]y with hollow structure is proposed by suppressing the speed and space of crystal growth. The as-prepared Na2- x Fe[Fe(CN)6 ]y hollow nanospheres show low vacancies and interstitial water content, leading to a high sodium content. As a result, the Na-rich Na1.51 Fe[Fe(CN)6 ]0.87 ·1.83H2 O hollow nanospheres exhibit a high initial Coulombic efficiency, excellent cycling stability, and rate performance via a highly reversible two-phase transition reaction confirmed by in situ X-ray diffraction. It delivers a specific capacity of 124.2 mAh g-1 at 17mA g-1 , presenting ultra-high rate capability (84.1 mAh g-1 at 3400mA g-1 ) and cycling stability (65.3% capacity retention after 1000 cycles at 170mA g-1 ). Furthermore, the as-reported non-aqueous ball-milling method could be regarded as a promising method for the scalable production of PBAs as cathode materials for high-performance SIBs.

Exploiting the Iron Difluoride Electrochemistry by Constructing Hierarchical Electron Pathways and Cathode Electrolyte Interface.

Conversion-type cathodes such as metal fluorides, especially FeF2 and FeF3 , are potential candidates to replace intercalation cathodes for the next generation of lithium ion batteries. However, the application of iron fluorides is impeded by their poor electronic conductivity, iron/fluorine dissolution, and unstable cathode electrolyte interfaces (CEIs). A facile route to fabricate a mechanical strong electrode with hierarchical electron pathways for FeF2 nanoparticles is reported here. The FeF2 /Li cell demonstrates remarkable cycle performances with a capacity of 300 mAh g-1 after a record long 4500 cycles at 1C. Meanwhile, a record stable high area capacity of over 6 mAh cm-2 is achieved. Furthermore, ultra-high rate capabilities at 20C and 6C for electrodes with low and high mass loading, respectively, are attained. Advanced electron microscopy reveals the formation of stable CEIs. The results demonstrate that the construction of viable electronic connections and favorable CEIs are the key to boost the electrochemical performances of FeF2 cathode.

Integrating Bi@C Nanospheres in Porous Hard Carbon Frameworks for Ultrafast Sodium Storage.

Sodium-ion batteries (SIBs) have emerged as an alternative technology because of their merits in abundance and cost. Realizing their real applications, however, remains a formidable challenge. One is that among the limitations of anode materials, the alloy-type candidates tolerate fast capacity fading during cycling. Here, a 3D framework superstructure assembled with carbon nanobelt arrays decorated with a metallic bismuth (Bi) nanospheres coated carbon layer by thermolysis of Bi-based metal-organic framework nanorods is synthesized as an anode material for SIBs. Due to the unique structural superiority, the anode design promotes excellent sodium-storage performance in terms of high capacity, excellent cycling stability, and ultrahigh rate capability up to 80Ag-1 with a capacity of 308.8mAhg-1 . The unprecedented sodium-storage ability is not only attributed to the unique hybrid architecture, but also to the production of a homogeneous and thin solid electrolyte interface layer and the formation of uniform porous nanostructures during cycling in the ether-based electrolyte. Importantly, deeper understanding of the underlying cause of the performance improvement is illuminated, which is vital to provide the theoretical basis for application of SIBs.

Insights into Synergistic Effect of g-C3N4/Graphite Heterostructures for Boosting Sodium Ion Storage with Long Cycle Stability

Sodium-ion batteries (SIBs) have attracted significant attention as promising next-generation energy storage devices. However, the research and development of SIBs are still in their infancy due to the lack of suitable high-performance anode materials. As a commercial anode material for lithium-ion batteries (LIBs), graphite often shows a low sodium storage capacity. Herein, a graphite heterojunction material was prepared through a facile ball-milling method. During the ball-milling process, a defect-enriched g-C3N4/graphite heterojunction was formed and the nitrogen-containing functional groups were regulated, which promoted the sodium storage capacity. The resulting g-C3N4/graphite electrode can exhibit excellent long cycle stability and rate performance, delivering a high reversible capacity of 202 mAh g–1 at 1.0 A g–1 after 6000 cycles and 90.06 mAh g–1 at 5.0 A g–1 after 10000 cycles. Moreover, an ultrahigh rate capability can also be obtained at 1.0 A g–1 with a capacity of 111 mAh g–1. The superiority of heterostructures for sodium storage and diffusion was proved via DFT calculations, which verified the synergistic effect between graphite and g-C3N4. This study provides a simple and efficient method for preparing g-C3N4/graphite heterostructures as well as a deep insight into the sodium storage mechanism of a heterostructure anode.