Buffer Volume Change Research Articles

Rigid-flexible mediated Co-polyimide enabling stable silicon anode in lithium-ion batteries

Silicon is considered as a promising electrode materials for the next generation of lithium-ion batteries. However, it’s commercial applications are hindered by significant volume changes. In this study, copolyimide binders with adjustable rigidity and flexibility were synthesized through simple copolymerization. The rigid segments containing adenine groups (p-APA) provide excellent mechanical strength and interface interaction, while flexible segments containing siloxane bonds and alkane chains (DS-NH2) can buffer volume changes through enhanced mobility and topological entanglement of molecular segments. Optimizing the copolymerization ratio helps minimize damage to the silicon electrode structure and stabilizes solid electrolyte interphase (SEI) growth. Compared to the rigid polyimide binders, rigid-flexible coupling strategy improves cycling stability, remaining a capacity of 2170 mAh/g at 2 A/g after 200 cycles and exhibiting stable cycling for over 750 cycles with a capacity limitation of 1500 mAh/g. The high mass loading silicon anodes, micron-sized silicon oxide electrodes and the full cells also exhibit favorable electrochemical performance. This research provides valuable insights for designing high-performance aromatic polymer binders for high energy density lithium-ion batteries.

Dual Strategy of Morphology Optimization and Interlayer Expansion in VS2 Cathode Toward High-Performance Mg-Li Hybrid Ion Batteries.

Combining the merits of the dendrite-free formation of a Mg anode and the fast kinetics of Li ions, the Mg-Li hybrid ion batteries (MLIBs) are considered an ideal energy storage system. However, the lack of advanced cathode materials limits their further practical application. Herein, we report a dual strategy of morphology optimization and interlayer expansion for the construction of hierarchical flower-like VS2 architecture coated by N-doped amorphous carbon layers. This tailored hierarchical flower-like structure coupled with homogeneous N-doped amorphous carbon layers cooperatively provide more active sites and buffer volume changes, thus realizing the enhancement of capacity and structural stability. Moreover, the enlarged interlayer spacing caused by the cointercalation of polyvinylpyrrolidone and ammonium ions can effectively promote the charge transfer rate and facilitate the rapid ion diffusion, as further demonstrated by electrochemical results and theoretical calculations. These features endow the hierarchical flower-like VS2 cathode with superior specific energy density (644.4 Wh kg-1, average voltage of 1.2 V vs Mg2+/Mg) and excellent rate capability (181.1 mAh g-1 at 2000 mA g-1). Systematic ex situ characterization measurements are employed to reveal the ion storage mechanism, which confirms that Li+ storage plays a leading role in the capacity contribution of MLIBs. Our strategy is in favor of providing useful insights to design and construct MLIBs with high energy density and excellent rate performance.

Influence of Polypyrrole on Phosphorus- and TiO2-Based Anode Nanomaterials for Li-Ion Batteries.

Phosphorus (P) and TiO2 have been extensively studied as anode materials for lithium-ion batteries (LIBs) due to their high specific capacities. However, P is limited by low electrical conductivity and significant volume changes during charge and discharge cycles, while TiO2 is hindered by low electrical conductivity and slow Li-ion diffusion. To address these issues, we synthesized organic-inorganic hybrid anode materials of P-polypyrrole (PPy) and TiO2-PPy, through in situ polymerization of pyrrole monomer in the presence of the nanoscale inorganic materials. These hybrid anode materials showed higher cycling stability and capacity compared to pure P and TiO2. The enhancements are attributed to the electrical conductivity and flexibility of PPy polymers, which improve the conductivity of the anode materials and effectively buffer volume changes to sustain structural integrity during the charge and discharge processes. Additionally, PPy can undergo polymerization to form multi-component composites for anode materials. In this study, we successfully synthesized a ternary composite anode material, P-TiO2-PPy, achieving a capacity of up to 1763 mAh/g over 1000 cycles.

A flexible plane-wire MoO2-anchored carbon nanofiber matrix as freestanding anodes for lithium storage with enhanced cyclability

Inspired by beds of silkworm cocoon, a flexible ″plane-wire″ MoO2-anchored carbon nanofiber matrix has been successfully prepared through electrospinning and subsequent annealing processes. It delivers an initial discharge capacity of 877 mAh g−1 at 200 mA g−1 with a high initial coulombic efficiency of 84.7 % and showcases a high reversible specific capacity of 743 mAh g−1 in the second cycle when employed as free-standing anodes for lithium batteries. It also exhibits good rate performance and superb cyclability, which delivering a specific capacity of 364 mAh g−1 at a high current density of 2 A g−1 and maintains a notable specific capacity of 674 mAh g−1 even after 2000 cycles. It is found that, the carbon nanofiber matrix serves as a robust electronic conductive network to reduce the charge transfer resistance and promote the transportation of Li+, and provides excellent support to buffer volume changes of the MoO2, resulting in enhanced rate performance and cyclability. Moreover, these electrodes are designed to be free-standing, which can improve the flexibility of the electrode and initial coulombic efficiency. It is believed that the as-prepared ″plane-wire″ MoO2-anchored carbon nanofiber matrix is a promising anode material for high-performance LIBs.

Decorating N-doped carbon-coated cobalt phosphide nanoparticles onto N-doped carbon nanotubes for high-performance supercapacitors and efficient methanol electro-oxidation

Cobalt phosphide (CoP) has become a promising electrode material for supercapacitors and methanol electro-oxidation due to its high electrical conductivity and and multiple oxidation states. However, the insufficient electroactive sites and large volume changes restrict its electrochemical performance. Herein, a novel CoP/carbon nanocomposite electrode material is designed and synthesized by decorating N-doped carbon (NC) coated CoP nanoparticles onto N-doped carbon nanotubes (N-CNTs). N-CNTs serve as support to grow CoP nanoparticles, which effectively reduces the sizes and aggregation of CoP nanoparticles and provides more electroactive sites. Density function theory calculation results confirm that the coating of NC on CoP nanoparticles increases the electrical conductivity of CoP by transferring electrons from NC to CoP. Meanwhile, a built-in electrical field is formed at the CoP/NC interface, resulting in higher electron/ion transfer efficiency as well as easier surface OH– adsorption. Moreover, the flexible NC shell and N-CNTs supports together effectively withstand the mechanical stress and buffer volume changes of CoP during the charge/discharge processes. Therefore, the obtained N-CNTs@CoP@NC nanocomposite electrode demonstrates high specific capacities (1003 and 621C g−1 at 1 and 10 A g−1, respectively) and good cycling performance (91.2 % retention of initial capacity after 10,000 cycles at 5 A g−1). Furthermore, it also shows a current density of up to 281 mA cm−2at a scan rate of 10 mV s−1with 92.4 % retention of initial current density in 1 M KOH with 0.5 M methanol. These results highlight a feasible strategy for improving practical capacities and cyclic stability of CoP-based electrode materials by integrating nanostructured CoP with one/two-dimensional carbon materials.

Fluffy ultrathin WO3 nanoneedle clusters in-situ grown in mesoporous hollow carbon nanospheres as advanced anode for lithium-ion batteries

Fluffy ultrathin WO3 nanoneedle clusters are in-situ grown in mesoporous hollow carbon nanospheres (MHCSs) via unique material impregnation and confined molten reaction in MHCS nanoreactors. Through transmission electron microscopy, scanning electron microscopy, X-ray diffraction, Raman spectra and X-ray photoelectron spectroscopy analyses, it can be found that WO3 nanoneedles with 5–10 nm in thickness and ∼140 nm in length are encapsulated within each MHCS with 150–250 nm in diameter and 30–40 nm in shell thick. Thermal gravimetric analysis reveals the WO3 content of 83.5 wt%. Lithium storage performance was evaluated by galvanostatic charge/discharge cycling, cyclic voltammogram and electrochemical impedance spectroscopy. The composite exhibits remarkable rate performance (average discharge capacity of 1352 mAh g−1 at 0.1 A g−1 and 105 mAh g−1 at 10 A g−1) and excellent cycling performance (1094 mAh g−1 at 0.2 A g−1 after 50 cycles, 760 mAh g−1 at 1 A g−1 after 500 cycles, 351 mAh g−1 at 5 A g−1 after 2000 cycles). The composite also presents outstanding kinetics properties, such as high Li+ diffusion coefficient, strong capacitive effect, and low electrochemical impedance. The superior electrochemical performance is attributed to unique “ship-in-a-bottle” structure. MHCSs facilitate electron transfer and ion diffusion, buffer volume change of WO3 and maintain the integrity of WO3. Furthermore, fluffy ultrathin nanoneedle cluster structure endows WO3 with high electrochemical activity.

Self-assembled VS2 microflowers buffering volume change during charging and discharging towards high-performance zinc ion batteries

VS2 has attracted increasing attention as a cathode material for aqueous zinc ion batteries because of its proper large layer spacing, weak interlayer interactions, multiple valence states of V, and excellent electrical conductivity, but its large volume change during charging and discharging leads to poor cycling stability. Herein, we report a one-step hydrothermal synthesis of VS2 microflowers with proper lamellar spacing, which provides a stable framework for the insertion/deinsertion of zinc ions and enhances the cycling stability, delivering an initial charge capacity of 128.3 mAh g−1 at 3 A g−1 and maintains a charge capacity of 100.1 mAh g−1 after 900 cycles. In addition, the optimized VS2 cathode shows specific capacities of 215.7 and 150.5 mAh g−1 at the current densities of 0.1 and 2 A g−1, respectively, demonstrating that the microflower structure with a high specific surface area and a short diffusion distance also significantly enhances the rate performance.

Constructing nickel sulfide @ nickel boride hybrid nanosheet arrays with crystalline/amorphous interfaces for supercapacitors

Designing a heterostructure with unique morphology and nanoarchitecture is regarded as an efficient strategy to achieve high-energy-density supercapacitors (SCs). Herein, a rational nickel sulfide @ nickel boride (Ni9S8@Ni2B) heterostructure is in situ synthesized on carbon cloth (CC) substrate via a simple electrodepositon strategy followed by a chemical reduction method. The three-dimensional hierarchically porous Ni9S8@Ni2B nanosheet arrays, consisting of crystalline Ni9S8 nanosheets and amorphous Ni2B nanosheets, can expose ample electroactive centers, shorten ion diffusion distance, and buffer volume changes during charging/discharging process. More importantly, the generation of crystalline/amorphous interfaces in the Ni9S8@Ni2B composite modulates its electrical structure and improves electrical conductivity. Owing to the synergy of Ni9S8 and Ni2B, the as-synthesized Ni9S8@Ni2B electrode acquires a specific capacity of 901.2C g−1 at 1 A g−1, a sound rate capability (68.3% at 20 A g−1), along with good cycling performance (79.7% capacity retention over 5000 cycles). Additionally, the assembled Ni9S8@Ni2B//porous carbon asymmetric supercapacitor (ASC) exhibits a cell voltage of 1.6 V and a maximum energy density of 59.7 Wh kg−1 at 805.2 W kg−1. These findings might offer a simple and innovative approach to fabricate advanced electrode materials for high-performance energy storage systems.

Development of carbon materials for sulfur cathodes in inorganic-based solid-state lithium–sulfur batteries

Inorganic-based solid-state lithium–sulfur batteries (SSLSBs) with high energy density and high safety have attracted wide attention as they are one of the most promising energy storage devices to meet future market requirements. However, the development of SSLSBs faces various challenges due to the unreasonable structural design in sulfur cathodes. Carbon is one of the indispensable components in sulfur cathodes. The rational design of carbon materials becomes an important strategy to address the challenges in sulfur cathodes. This review summarizes recent literature about the design and application of carbon materials for sulfur cathodes in inorganic-based SSLSBs. It starts with the introduction of different carbon materials from zero-dimensional to three-dimensional carbon materials. Particularly, this review paper highlights the structural design of carbon materials and the cathode fabrication methods, toward improving the conductivity of cathodes, buffering volume changes in cathodes, reducing interfacial resistance among cathode components, and increasing the mass loading of active materials. Finally, the existing challenges and promising solutions for carbon materials in the cathodes are discussed and proposed.

Nano Sn-SnOx embedded in multichannel hollow carbon nanofibers: Microstructure, reversible lithium storage property and mechanism

To ameliorate the lithium storage property of tin-based oxides, nano Sn-SnOx embedded in multichannel hollow carbon nanofibers (Sn-SnOx@MCNF) were identified in this work. Multichannel hollow carbon nanofibers embedded uniformly by amorphous SnOx and proper Sn nanocrystals with various valence states of Sn endowed Sn-SnOx@MCNF quick ion transfer rate, enough catalytic active sites, high structure stability, little agglomeration and superior buffering volume change during alloying/dealloying processes. Accordingly, Sn-SnOx@MCNF-based electrodes possessed predominant reversibility, large capacity and excellent rate capability during the process of lithium intercalation of SnOx to Li2O and LixSn. When applied in practice, the present Sn-SnOx@MCNF-based electrodes expressed a high reversible capacity of 669.2 mAh g−1 even after 600 cycles at 1.0 A g−1 and a high-rate capacity of 525.1 mAh g−1 at 4.0 A g−1. Sn-SnOx@MCNF will be a potential anode material for Li-ion batteries with superior Li-storage performance. The synergistic enhancement mechanism between MCNF and nano Sn-SnOx was proposed in detail.

Grape-cluster-like hierarchical structure of FeS2 encapsulated in graphitic carbon as cathode material for high-rate lithium batteries

A unique grape-cluster-like hierarchical structure in which FeS2 is encapsulated in graphitic carbon (FeS2@GC) composite has been elaborately designed to address the limitations in rechargeable Li-FeS2 batteries, such as poor electronic/ionic conductivity, dissolved polysulfide intermediates, and large volume changes. In particular, the individual grape grain of FeS2@GC particle with a yolk-shell structure that graphitic carbon shell and FeS2 nanoparticle core can significantly enhance the electrical conductivity, buffer volume changes, and confine the generated polysulfide intermediates. Thus, these high-efficiency individuals as the reaction units can facilitate the electrochemical redox reactions, improving the reaction kinetics. In addition, the closely connected individual FeS2@GC particles can construct a grape cluster to further enhance the electrical conductivity, facilitating ion/electron transport in the electrode. Consequently, the FeS2@GC composite demonstrates excellent electrochemical and stable cycling performances, particularly at high C-rates. A reversible capacity of 661 mAh g−1 after 200 cycles at 1 C, corresponding to a capacity retention of 97.5% of 2nd cycle (678 mAh g−1), and a capacity decay rate of 0.012% per cycle are achieved. Even at a higher rate of 10 C, a high capacity retention of 407 mAh g−1 after 1000 cycles is maintained, which indicates excellent cycling stability and superior rate capability.

MoS2/MoO2 nanosheets anchored on carbon cloth for high-performance magnesium- and sodium-ion storage

Developing new types of rechargeable metal-ion batteries beyond lithium-ions, including alkaline ion (such as Na+, K+) and multivalent ion (such as Mg2+, Zn2+, Ca2+ and Al3+) batteries, is progressing quickly towards large-scale energy storage systems. However, the major obstacle to their large-scale applications has been a lack of appropriate electrode materials with reversible metal ions insertion/extraction behavior, resulting in inferior electrochemical performance. Here we develop a well-designed MoS2/MoO2 hybrid nanosheets anchored on carbon cloth (MoS2/MoO2/CC) as electrode materials. This rational design can effectively shorten ion diffusion distance, increase electric conductivity of the electrode, and buffer volume change. Benefiting from the synergistic effect of structural and compositional features, the MoS2/MoO2/CC electrode exhibits high initial reversible capacities (326 mA h g−1 at 0.1 A g−1 in magnesium-ion storage; 1270 mA h g−1 at 0.1 A g−1 in sodium-ion storage), excellent rate capacities (57 mA h g−1 at 10 A g−1 in magnesium-ion storage; 335 mA h g−1 at 5 A g−1 in sodium-ion storage) and long-term cycling stability (105 mA h g−1 after 600 cycle at 1 A g−1 in magnesium-ion storage; 208 mA h g−1 after 600 cycles at 5 A g−1 in sodium-ion storage). We expect that the multi-engineering strategy will provide some valuable insights for the development of other advanced electrode materials for high-performance metal-ion batteries.

Hybrid coating SnO2 for enhanced Li ions storage

Anode SnO2 in lithium-ion batteries suffers from volume expansion and agglomeration. Here, the SnO2 nanoparticles are hybrided with ZrO2 particles by the support of carbon nanotube networks. The obtained SnO2/C/ZrO2 composite shows improved electrochemical performances. Investigations reveal that the carbon nanotubes shorten the transmission path of electrons and Li+ ions. Ball milling with ZrO2 promotes the formation of nanosized SnO2 to weaken the internal strain change, being beneficial to buffering volume change during electrochemical cycling afterwards. High-resolution 6,7Li NMR investigations indicate that conversion and alloying reactions are stepwise involved for SnO2/C/ZrO2 anode. The strategy of designing SnO2/C/ZrO2 composite from the morphology-controlled metal-organic frameworks for energy storage widens the possibility to fabricate promising materials with enhanced performances.

Molybdenum Nitride and Oxide Quantum Dot @ Nitrogen-Doped Graphene Nanocomposite Material for Rechargeable Lithium Ion Batteries

A multistage architecture with molybdenum nitride and oxide quantum dots (MON-QDs) uniformly grown on nitrogen-doped graphene (MON-QD/NG) is prepared by a facile and green hydrothermal route followed by a one-step calcination process for lithium ion batteries (LIBs). Characterization tests show that the MON-QDs with diameters of 1–3 nm are homogeneously anchored on or intercalated between graphene sheets. The molybdenum nitride exists in the form of crystalline Mo2N (face-centered cubic), while molybdenum oxide exists in the form of amorphous MoO2 in the obtained composite. Electrochemical tests show that the MON-QD/NG calcinated at 600 °C has an excellent lithium storage performance with an initial discharge capacity of about 1753.3 mAh g−1 and a stable reversible capacity of 958.9 mAh g−1 at current density of 0.1 A g−1 as well as long-term cycling stability at high current density of 5 A g−1. This is due to the multistage architecture, which can provide plenty of active sites, buffer volume changes of electrode and enhance electrical conductivity as well as the synergistic effect between Mo2N and MoO2.

Construction of in-plane 3D network electrode strategy for promoting zinc ion storage capacity

The energy density and mechanical flexibility of the reported zinc ion microcapacitors (ZIMCs) require further improvement to meet the rapid development and modularization of miniaturized and self-powered electronic systems. Herein, a flexible ZIMC with composite "honeycomb" three-dimensional (3D) network structure was creatively assembled using a low-cost blade-coating and foaming technique. MnO2 and MXene uniformly coating onto this 3D network structure with in-plane open-holes were used as the cathode and anode, respectively. The unique configuration endows the electrodes with large specific surface area, more loading active materials and fully exposed active sites, which is conducive to electrons and ions transport and electrolyte penetration. And the specific capacitance of ZIMC can reach up to 264 mF cm−2, energy density with 132 μWh cm−2, power density with 1510 μW cm−2. In addition, this composite "honeycomb" 3D network structure displays excellent mechanical property with tensile stress of 19.33 MPa and strain of 4.52%, which can buffer volume changes and enhance the structural stability of the device (the capacitance retention over 90% after 6700 cycles). Therefore, the development of electrode materials for ZIMC with this reliable and stable 3D network structure has great potential in the field of wearable electronics.

Colloidal silicon dioxide assisted ethylene glycol combustion synthesis of mesoporous zinc manganate for lithium ions storage

Mesoporous zinc manganate (ZnMn2O4) hollow architectures made up of interlinked nanoparticles have been successfully prepared through a colloidal silicon dioxide (SiO2)-assisted ethylene glycol (EG) combustion process. The dosage of colloidal SiO2 plays a vital role in the morphology and specific surface area (SSA). The SSA of ZnMn2O4-EG-400 can achieve 163.2 m2 g−1 with the pore sizes mainly centered at 3.5, and 5.1 nm when the volume of colloidal silica is 400 μL. The hierarchical mesoporous feature of ZnMn2O4 hollow architectures makes it a potential electroactive material for lithium-ion storage. When mesoporous ZnMn2O4-EG-400 is employed in lithium-ion batteries, the mesoporous zinc manganate appears large specific capacity, remarkable rate performance, and durability. A reversible capacity of 384.4 mAh g–1 can be gained after 500 continuous galvanostatic charge/discharge (GCD) cycles at 1 A g–1. The outstanding lithium ions storage performance can be attributed to the high SSA and hierarchical mesoporous traits, which can afford abundant active sites, raise the contact area between Li+ and ZnMn2O4, and buffer volume change during consecutive electrochemical processes.

High-donor electrolyte endows graphite with anion-derived interphase to achieve stable K-storage

Graphite anodes are expected to be applied in potassium-ion batteries, but it is limited by uncontrolled volume fluctuation and dendrite growth during cycles. Herein, an anion-derived interphase with high mechanical strength and ionic conductivity is constructed to address the aforementioned issues using an amide-based electrolyte. The high-donor number for an amide molecule can strengthen the solvation with K+, ensuring more anions enter the primary solvation sheath. The shortened distance is in favor of the electron transfer from the solvated K+ to the anion and subsequently motivates the anion reduction. The obtained inorganic-rich interphase buffers volume change, suppresses K dendrite propagation, and facilitates ion diffusion. Based on these, symmetric K//K cells could operate stable plating and stripping with a small polarization of 0.15 V for over 2800 h. The graphite electrode achieves a highly reversible phase transition of C↔KC60↔KC48↔KC36↔KC24↔KC8. A high discharge capacity of 217.6 mA h g−1 with retention of 86.9% is obtained after 100 cycles. The assembled full battery also exhibits a high energy density of 52.5 W h kg−1. This work highlights the importance of the interfacial structure and provides a brand-new strategy for designing high-performance electrolytes.

Si nanoplates prepared by ball milling photovoltaic silicon sawdust waste as lithium-ion batteries anode material

High-purity Si sawdust waste from the photovoltaic industry is an available source for Si anodes of lithioum-ion batteries (LIBs), but seeking for a synthetic process featuring with low cost and industrial scale from the Si waste to nanoscale Si materials in actual applications is quite challenging. Herein, we report a highly scalable and cost-effective ball milling method that directly converts photovoltaic Si sawdust waste to Si nano-plate (BM Si) for LIBs’ anode material. In the ball milling process, a thin SiO2 layer generates on BM Si. The nanoscale size of BM Si and SiO2 layer can buffer volume change of Si anode during cycling. As a result, BM Si displays a high initial capacity of 2196 mAh/g and remains a stable capacity of 1480 mAh/g after 100 cycles at 100 mA g−1, which is higher than that of commercial Si nanoparticles.

Buffering Volume Change in Solid-State Battery Composite Cathodes with CO2-Derived Block Polycarbonate Ethers.

Polymers designed with a specific combination of electrochemical, mechanical, and chemical properties could help overcome challenges limiting practical all-solid-state batteries for high-performance next-generation energy storage devices. In composite cathodes, comprising active cathode material, inorganic solid electrolyte, and carbon, battery longevity is limited by active particle volume changes occurring on charge/discharge. To overcome this, impractical high pressures are applied to maintain interfacial contact. Herein, block polymers designed to address these issues combine ionic conductivity, electrochemical stability, and suitable elastomeric mechanical properties, including adhesion. The block polymers have “hard-soft-hard”, ABA, block structures, where the soft “B” block is poly(ethylene oxide) (PEO), known to promote ionic conductivity, and the hard “A” block is a CO2-derived polycarbonate, poly(4-vinyl cyclohexene oxide carbonate), which provides mechanical rigidity and enhances oxidative stability. ABA block polymers featuring controllable PEO and polycarbonate lengths are straightforwardly prepared using hydroxyl telechelic PEO as a macroinitiator for CO2/epoxide ring-opening copolymerization and a well-controlled Mg(II)Co(II) catalyst. The influence of block polymer composition upon electrochemical and mechanical properties is investigated, with phosphonic acid functionalities being installed in the polycarbonate domains for adhesive properties. Three lead polymer materials are identified; these materials show an ambient ionic conductivity of 10 –4 S cm–1, lithium-ion transport (tLi+ 0.3–0.62), oxidative stability (>4 V vs Li+/Li), and elastomeric or plastomer properties (G′ 0.1–67 MPa). The best block polymers are used in composite cathodes with LiNi0.8Mn0.1Co0.1O2 active material and Li6PS5Cl solid electrolyte–the resulting solid-state batteries demonstrate greater capacity retention than equivalent cells featuring no polymer or commercial polyelectrolytes.

Constructing three-dimensional (3D) nanoflower-like Cu2-xSe-MoSe2 heterojunction as an excellent long-life and high-rate anode for half/full Na-ion batteries

Transition metal selenides with good economy and high theoretical capacity are the most attractive anode materials for sodium-ion batteries (SIBs). However, the severe volume expansion during sodiumization/desodiumization still hinders the wide application of this material. Nano heterojunction materials with lattice distortion not only improve the thermal stability and reaction kinetics, but also the contact area between active materials and electrolyte is increased to enhance the cycle and rate. Herein, three-dimensional (3D) nanoflower-like Cu2-xSe-MoSe2 (CMSe) heterojunction is successfully prepared through a facile co-precipitation and hydrothermal method, the prepared 3D CMSe heterojunction anode for SIBs exhibits a high reversible capacity of 549.1 mAh g−1 over 100 cycles at 0.2 A g−1, superior rate capability of 350.59 mAh g−1 at 20 A g−1, and excellent cycling stability (335 mAh g−1 at 2.0 A g−1 over 4000 loops). The excellent sodium storage performance can be ascribed to its 3D nanoheterojunction structural features, which can enhance the contact area with electrolyte, buffer volume changes, improve its structural stability during cycling. In addition, the deep reaction mechanism is sufficiently explored by means of ex situ XRD and HRTEM. When further coupled with Na3V2(PO4)3 cathode in sodium-ion full cells, it also delivers excellent electrochemical performance. Therefore, 3D CMSe heterojunction is promising anode materials for SIBs.