High Initial Coulombic Efficiency Research Articles

Amorphous MoO2/C Nanospheres–Porous Graphene Composites for Pseudocapacitive Li Storage

Amorphous MoO2 nanostructures are regarded as promising anode materials for lithium-ion batteries (LIBs) due to their unusually high capacity. However, designing an amorphous MoO2 nanostructure with satisfactory performance still remains greatly challenging owing to the poor conductivity and unstable structure. In this study, a hierarchically porous composite composed of amorphous MoO2/C nanospheres and interconnected graphene networks (MoO2/C-rGO) was fabricated by a convenient route. Thanks to the oxygen-deficient amorphous nanostructure, open diffusion channels, and continuous conductive networks, the electrochemical performance of the composite has been significantly enhanced. Specifically, it delivers an extraordinary initial discharge capacity of 1328 mA h g–1 at 0.1 A g–1, a high initial Coulombic efficiency (CE) of 82.6%, an impressive rate capability of 444 mA h g–1 at 8.0 A g–1, and a good cyclability with 642 mA h g–1 after 500 cycles at 1.0 A g–1. Electrochemical analysis indicates that the Li storage of MoO2/C-rGO is dominated by a pseudocapacitive mechanism, which allows rapid insertion/extraction of Li+ without damaging the structure of the electrode, thus achieving structural and electrical integrity.

Understanding the formation of a cubic Mn0.6Fe0.4S solid-solution anode and its high performance for rechargeable lithium-ion batteries

A cubic Mn 0.6 Fe 0.4 S solid solution material has been synthesized using a scalable in situ sulfuration treatment of Prussian-blue analogs (PBAs), and its phase formation process and Li-storage mechanism were investigated. Increased treatment temperature and time encourage a phase transformation from hexagonal Fe 7 S 8 to cubic FeS 2 during the sulfuration process, which results in the formation of a solid solution between cubic FeS 2 and cubic MnS. The resulting Mn 0.6 Fe 0.4 S solid solution electrode exhibits high initial coulombic efficiency, excellent rate performance, and superior cycling stability (520 mA h g −1 after 1000 cycles at 1.0 A g –1 ). Ex-situ X-ray diffractometry and electro-kinetics tests show that the doping-induced structural phase transition in Mn 0.6 Fe 0.4 S solid solution creates a favorable electronic structure and ensures rapid charge transfer kinetics during the lithiation/delithiation process, simultaneously achieving high energy conversion efficiency and a long lifespan. • Cubic Mn 0.6 Fe 0.4 S solid solution as anode material is successfully synthesized. • The phase transition from α-MnS to metastable β-MnS could be induced in the charge process. • The improvement in electrochemical performance is attributed to the doping-induced structural phase transition in Mn0.6Fe0.4S.

Construction of SnS-Mo-graphene nanosheets composite for highly reversible and stable lithium/sodium storage

• We report the simple synthesis of ternary SnS-Mo-GNs composite. • The composite has the structure of SnS nanoparticles tightly bonded with Mo and GNs. • The Mo and GNs function as dual buffer to suppress the Sn agglomeration during cycling. • The composite exhibits superior reversibility and cycleability for Li/Na-storage. Sn-based chalcogenides are considered as one of the most promising anode materials for lithium-ion batteries (LIBs) because of their high capacities through both conversion and alloying reactions. However, the realization of full capacities of Sn-based chalcogenides is mainly hindered by the large volume variation and inferior reversibility of conversion reaction during cycling. In present work, a new ternary SnS-Mo-graphene nanosheets (SnS-Mo-GNs) composite is fabricated by a simple and scalable plasma milling method, in which SnS nanoparticles are tightly bonded with Mo and GNs. The Mo and GNs additives can effectively alleviate the large volume change of SnS upon cycling, which leads to a stable electrochemical framework. Moreover, they can significantly suppress the Sn agglomeration in lithiated SnS, which enables highly reversible conversion reaction during cycling. As anode for LIBs, the SnS-Mo-GNs composite exhibits a high initial coulombic efficiency of 86.9% (almost complete reversibility of SnS, ∼97.3%), high cyclic coulombic efficiency after initial three cycles (> 99.5%), and long lifespan (up to 600 cycles). Moreover, it also demonstrates superior electrochemical performance for sodium storage. Thus, this work demonstrates a potential anode for batteries application and provides a viable strategy to obtain highly reversible and stable anodes for lithium/sodium storage.

Improved Na-ion kinetics of 1T MoS2 nanopatterned porous hard carbon as an ultra-long life anode

Porous hard carbons (PHC) are promising anode materials in sodium-ion batteries; however, the availability of large surface area creates numerous irreversible active sites that cause rapid initial cycle capacity fading and electrode degradation, resulting in lower specific capacity and poor cycle stability. PHC surface modification via 2D transition metal dichalcogenides is a synergistic approach to combine excellent electrochemical properties of both materials and resolve these issues. Therefore, we designed 1T MoS2 nanopatterned PHC skeleton using carbonization and hydrothermal treatment of biomass (chickpea husk). As a result, HC@MoS2-II electrode with extended d002 spacing of MoS2 nanolayers (0.650 nm) exhibited an excellent specific capacity of 470 mAh/g at 50 mA/g with high initial coulombic efficiency (63%) and ultra-long cycle stability (190 mAh/g) at 1000 mA/g over 3500 cycles. The extraordinary electrochemical performance can be attributed to the synergistic assembly, where the high surface area PHC skeleton effectively buffered large volume expansion during charging/discharging, and 1T MoS2 nanoflowers added fast ionic diffusion kinetics and PHC surface protection.

Restraining the escape of lattice oxygen enables superior cyclic performance towards high-voltage Ni-rich cathodes.

Layered Ni-rich cathodes, operating at high voltage with superior cyclic performance, are required to develop future high-energy Li-ion batteries. However, the worst lattice oxygen escape at the high-voltage region easily causes structural instability, rapid capacity fading and safety issues upon cycling. Here, we report a dual-track strategy to fully restrain the escape of lattice oxygen from Ni-rich cathodes within 2.7-4.5V by one-step Ta doping and CeO2 coating according to their different diffusion energy barriers. The doped Ta can alleviate the charge compensation of oxygen anions as a positive charge centre to reduce the lattice oxygen escape and induce the formation of elongated primary particles, significantly inhibiting microcrack generation and propagation. Additionally, the layer of CeO2 coating effectively captures the remaining escaped oxygen and then the captured oxygen feeds back into the lattice during subsequent discharge. The resultant Ni-rich cathode enables a capacity of 231.3mAhg-1 with a high initial coulombic efficiency of 93.5%. A pouch-type full cell comprising this cathode and a graphite anode exhibits >1000 times life cycles at 1C in the 2.7-4.5V range, with 90.9% capacity retention.

Electrochemically Active Mn-Doped Iron Hexacyanoferrate as the Cathode Material in Sodium-Ion Batteries

In this work, for the performance enhancement of iron hexacyanoferrate, an electrochemically active Mn-doped iron hexacyanoferrate cathode is fabricated via a bottom-up approach. It is found that the pre-treatment of interstitial water and appropriate Mn doping are two keys to achieving higher capacity and higher stability. The interstitial water has a trade-off effect between the alleviation of volume expansion upon Na+ (de)intercalation and the retardation of Na-ion diffusion. The moisture-tailored iron hexacyanoferrate with appropriate Mn doping exhibits a high initial Coulombic efficiency of 94.8%, enhanced capacity and rate performance, and excellent cycling stability. These results benefit from the fact that the extraction/insertion of Na ions from/into the lattice via a solid-solution mechanism correspond to both the slight volume expansion and fast sodium diffusion rate; otherwise, the removal of interstitial water and a higher Mn content might lead to poor cycling stability due to excessive volume expansion resulting from rhombohedral to cubic phase transformation. Finally, the less demand on the control of air humidity for the fabrication of electrodes and the potential for the full cell coupled with hard carbon are also demonstrated, which shows great potential for practical applications.

Sb nanocrystallites derived from industrial antimony white as promising alloying-type anodes for Na-ion batteries

Alloying-type anodes exhibit unique advantages in terms of capacity and working potentials for practical application in sodium-ion batteries (SIBs). Sb-based nanocrystallites are prepared through a low-cost and large-scalable route by reducing the industrial antimony white (Sb2O3) in aqueous solutions under mild conditions and studied as the anode materials of SIBs. Compared with the pristine Sb2O3 and partially reduced Sb/Sb2O3 hybrid, the totally reduced product (pure Sb nanocrystallite) manifests the most steady desodiation potential, highest capacity at around 0.75 V vs. Na+/Na, highest initial Coulombic efficiency, longest cycling life, and fastest charge/discharge rate. The different electrochemical performance of as-prepared materials is discussed from the perspective of Na-storage mechanisms. The results demonstrate that the as-prepared pure Sb nanocrystallite is more promising than its oxides for practical application in SIBs.

Unraveling the impact of metallic Sn on the reversible capacity of passionfruit-like C/SnO2/Sn@C as sodium-ion batteries anodes

Improving the reaction reversibility is a promising way to enhance the sodium-ion storage capability of SnO2-based anodes. In this work, we design the passionfruit-like C/SnO2/Sn@C as a high reversible capacity anode for sodium ion batteries (SIBs). The structural design of the passionfruit-like C/SnO2/Sn@C not only prevents the aggregation of primary SnO2 particles and limits their structural damage, but also finely accelerates electron diffusion rate, avoids interfacial side reactions and achieves the high reversible capacity. Simultaneously, the metallic Sn as a novel additive can accelerate sodium ion diffusion coefficient, and improve the alloying reaction reversibility. Compared to other SnO2-based electrodes, the passionfruit-like C/SnO2/Sn@C structure delivers a high initial coulombic efficiency (78.35%) and excellent reversible capacity (750.8 mAh g−1 at 0.2 A g−1). This work is expected to provide significant enlightenment in the introduction the corresponding metal phase into the metal oxide to enhance the reversible capacity and initial coulombic efficiency of sodium-ion batteries.

Mg2+ doping into Li sites to improve anionic redox reversibility and thermal stability of lithium-rich manganese-based oxides cathode

As a low cost and low atomic mass dopant, Mg2+ doping is often used to improve the electrochemical performance of lithium-rich manganese-based layered oxides (LRMO) cathode materials. However, the Mg2+ doping site is still controversial and its mechanism is not clear. In this work, Mg-doped LRMO was synthesized by a spray-drying method. It was proved that the Mg2+ is doped into the Li sites of the Li layers substituting partial ‘Li–O–Li’ with a stronger ‘Li–O–Mg’ configuration. The Mg-doped LRMO possesses a stable lattice structure and high reversibility of anionic redox reaction, which shows a high initial Coulombic efficiency of 89.0%, enhanced specific capacity (305.3 mAh/g at 0.1 C), cycling performance, and thermal stability in comparison with the pristine sample. The first-principle calculations reveal that the top of the O2p band of Mg-doped LRMO is lower about 0.81 eV, which implies a more stable lattice oxygen structure.

Highly N‐doped carbon with low graphitic‐N content as anode material for enhanced initial Coulombic efficiency of lithium‐ion batteries

AbstractN‐doped carbons as one of the most prominent anode materials to replace standard graphite exhibit outstanding Li+ storage performance. However, N‐doped carbon anodes still suffer from low N‐doping levels and low initial Coulombic efficiency (ICE). In this study, high N‐doped and low graphitic‐N carbons (LGNCs) with enhanced ICE were synthesized by taking advantage of a denitrification strategy for graphitic carbon nitride (g‐C3N4). In brief, more than 14.5 at% of N from g‐C3N4 (55.1 at% N) was retained by reacting graphitic‐N with lithium, which was subsequently removed. As graphitic‐N is largely responsible for the irreversible capacity, the anode's performance was significantly increased. Compared to general N‐doped carbons with high graphitic‐N proportion (>50%) and low N content (<15 at%), LGNCs delivered a low proportion of 10.8%–17.2% within the high N‐doping content of 14.5–42.7 at%, leading to an enhanced specific capacity of 1499.9 mAh g−1 at an ICE of 93.7% for the optimal sample of LGNC (4:1). This study provides a facile strategy to control the N content and speciation, achieving both high Li+ storage capacity and high ICE, and thus promoting research and application of N‐doped carbon materials.

High crystallinity potassium nickel hexacyanoferrate nanoparticles synthesized by improved precipitation way as cathodes for potassium-ion batteries

Due to the unique three-dimensional tunnel structure, Prussian blue analogues can reversibly de/intercalate K+ in crystal lattice and show original electrochemical properties. However, crystal water and vacancy inevitably appear in the framework controlled by synthesis process, limiting severely the potassium storage. Herein, high crystallinity K1.86Ni[Fe(CN)6]0.87·□0.13·1.88H2O was synthesized through electrostatic assisted coprecipitation technology, which effectively increased the initial potassium content. Moreover, the microstructure is affected under the action of static electricity, resulting in a nano-structure and large specific surface area (102.5 m2 g−1). Compared with the sample without electrostatic field, its electrochemical performances can be significantly improved with a high initial coulombic efficiency of 85.5%, capacity retention of 90.3% after 503 cycles at 1C and rate capability of 49 mAh g−1 at 10C. The new method opens up a way for the performance improvement of other Prussian blue-based cathodes.

Phosphorus/sulfur co-doped hard carbon with a well-designed porous bowl-like structure and enhanced initial coulombic efficiency for high-performance sodium storage

Hard carbon with high specific capacity and cost-effective characteristics has emerged as a critical material in the study of sodium-ion batteries (SIBs) anodes. However, their unsatisfactory initial coulombic efficiency (ICE) and ineluctable structural deformation during long-cycling work seriously hinder their application in practice. Here, phosphorus/sulfur co-doped hard carbon with a porous bowl-like structure (denoted as P/S-HCB) is developed to achieve high performance. The experimental data show that the doping of S increased the interlayer spacing of graphite in the surface/subsurface region, the doping of P promoted the formation of C-S-P and P-O bonds, which can contribute to abundant structural defects and redox reaction sites that not only improves structural stability but also contributes to the capacitive process under high rate. The as-fabricated P/S-HCB electrode demonstrates outstanding Na-ion storage performance regarding high ICE of 88.71%, the high-reversibility capacity of about 450 mA h g−1 after 140 cycles at 0.2 A g−1, extraordinary rate capability of 216.3 mA h g−1 at 10 A g−1, and long-term cycling stability of 276 mA h g−1 after 3000 cycles at 10 A g−1. These results show a novel approach to developing advanced hard carbon materials for sodium storage.

Fe3+-Derived Boosted Charge Transfer in an FeSi4P4 Anode for Ultradurable Li-Ion Batteries.

Ion and electron transportation determine the electrochemical performance of anodes in metal-ion batteries. This study demonstrates the advantage of charge transfer over mass transport in ensuring ultrastable electrochemical performance. Additionally, charge transfer governs the quality, composition, and morphology of a solid-electrolyte interphase (SEI) film. We develop FeSi4P4-carbon nanotube (FSPC) and reduced-FeSi4P4-carbon nanotube (R-FSPC) heterostructures. The FSPC contains abundant Fe3+ cations and negligible pore contents, whereas R-FSPC predominantly comprises Fe2+ and an abundance of nanopores and vacancies. The copious amount of Fe3+ ions in FSPC significantly improves charge transfer during Li-ion battery tests and leads to the formation of a thin monotonic SEI film. This prevents the formation of detrimental LiP and crystalline-Li3.75Si phases and the aggregation of discharging/recharging products and guarantees the reformation of FeSi4P4 nanocrystals during delithiation. Thus, FSPC delivers a high initial Coulombic efficiency (>90%), exceptional rate capability (616 mAh g-1 at 15 A g-1), and ultrastable symmetric/asymmetric cycling performance (>1000 cycles at ultrahigh current densities). This study deepens our understanding of the effects of electron transport on regulating the structural and electrochemical properties of electrode materials in high-performance batteries.

Easy Diameter Tuning of Silicon Nanowires with Low-Cost SnO2-Catalyzed Growth for Lithium-Ion Batteries.

Silicon nanowires are appealing structures to enhance the capacity of anodes in lithium-ion batteries. However, to attain industrial relevance, their synthesis requires a reduced cost. An important part of the cost is devoted to the silicon growth catalyst, usually gold. Here, we replace gold with tin, introduced as low-cost tin oxide nanoparticles, to produce a graphite–silicon nanowire composite as a long-standing anode active material. It is equally important to control the silicon size, as this determines the rate of decay of the anode performance. In this work, we demonstrate how to control the silicon nanowire diameter from 10 to 40 nm by optimizing growth parameters such as the tin loading and the atmosphere in the growth reactor. The best composites, with a rich content of Si close to 30% wt., show a remarkably high initial Coulombic efficiency of 82% for SiNWs 37 nm in diameter.

Li-Compound Anodes: A Classification for High-Performance Li-Ion Battery Anodes.

Four main anode types are generally considered as typical anodes for Li-ion batteries (LIBs): Li-metal, carbon-based, alloy-based, and oxide-based anodes. Although they exhibit satisfactory electrochemical performance as LIB anodes, they cannot simultaneously satisfy all key requirements for LIB anodes: high reversible capacity, high initial Coulombic efficiency (ICE), long cycle life, fast rate capability, structural stability, and no safety concerns. Here, we suggest Li-compound anodes as a promising class of high-performance LIB anodes. Three binary (LiSn, Li2Sb, and LiBi) and three ternary (Li2ZnSb, Li5GeP3, and Li5SnP3) Li compounds were introduced as Li-compound anodes. LiSn and Li5SnP3 were selected and further modified into their nanocomposites by solid-state synthetic routes using carbon sources for high-performance LIB anodes. The Li-compound nanocomposite anodes exhibited excellent performance and simultaneously fulfilled all the key requirements for high-performance LIB anodes. Therefore, Li-compound anodes are expected to be a promising and innovative category of high-performance LIB anodes.

A high-performance nano-Sn/G@C composite anode prepared by waste carbon residue from spent Lithium-ion batteries

The high-value utilization of waste carbon residue (WCR) from spent lithium-ion batteries (LIBs) enjoys great significance in environmental protection and economic growth. Here, a nano-SnO2/Graphite (nano-SnO2/G) precursor is synthesized with SnCl2 as the reducing agent by utilizing the defect characteristics indicating that the WCR surface has been severely oxidized and presented a porous structure. Firstly, the roasting conditions are optimized by the combination of orthogonal and single-factor experiments. The results showed that the nano-SnO2/G precursor with 41.41 % Sn loading is obtained via the molten-salt method under optimal conditions, and 99.97 %, 99.93 %, 99.93 %, 99.45 %, 95.89 %, and 97.83 % of Ni, Co, Mn, Al, Si, and Fe in the WCR can be removed. Subsequently, the mechanisms of microscopic atomic reactions in the molten-salt roasting are explored by the density functional theory simulations. Finally, the high-performance nano-Sn/G@C composite anode with a sandwich structure is prepared via carbothermal reduction. It exhibited a high initial Coulombic efficiency of 85.09 % and a reversible specific capacity of 650.9mAh/g at 100 mA/g. Moreover, the nano-Sn/G@C displayed ultra-stable cycling with a capacity fading rate of 0.034 % per cycle and reserved a high reversible specific capacity of 607.6mAh/g at 500 mA/g after 500 cycles. The proposed process represents a remarkable advancement in regenerating WCR into higher-value applications.

Co Substitution of Cationic and Transition Metal in O3-Type NaCrO2 Cathode for High Energy Density

The development of advanced cathode materials with high operating voltage and high reversible capacity is essential to promote the practical realization of sodium ion battery (SIB) technology. Here, O3 type Na0.9Ca0.035Cr0.97Ti0.03O2 is designed by Ca and Ti co-substitution in O3 type NaCrO2, and proposed as a new type of cathode material for high-energy density practical SIBs. On the basis of Chemical science, Alkalin ion successully incorporate NaO6 octahedron of Na0.9Ca0.035Cr0.97Ti0.03O2.1,2 In substitution process two Na+ per single Ca2+, while Cr3+ to Ti4+ ions.3,4 As a result Na+ vacancies are formed Na+ layer. Through co-substitution, structural stability of O3 – Na0.9Ca0.035Cr0.97Ti0.03O2 is increased, because stronger Ti – O bond and immobile Ca2+ ions in Na site synergistically make an effect the unit cell structures. This structural feature suppresses the irreversible phase transition and provide fast Na ion kinetics. In 1.5 – 3.8 voltage range, O3 – Na0.9Ca0.035Cr0.97Ti0.03O2 cathode to deliver the high initial Coulombic efficiency of 95%. Also at a 10 C rate, cathode retains the 90% of its initial capacity after 1000 cycles. In situ X-ray diffraction confirmed the reversible structure properties during charging and discharging process. Moreover, the cathode guarantees the practical applicability with good cycling in a pouch- type full cell using a hard carbon anode, as well as with excellent water durability. References J. J. Braconier, C. Delmas and P. Hagenmuller, Mat. Res. Bull., 1982, 17, 993–1000. J.-Y. Hwang, S.T. Myung and Y.K. Sun, Chem. Soc. Rev., 2017, 46, 3529–3614. L. Zheng, J.C. Bennett and M.N. Obrovac, J. Electrochem. Soc., 2019, 166, A2058–A2064.Y. Tsuchiya, K. Takanashi, T. Nishinobo, T. Ohta and N. Yabuuchi, Chem. Mater., 2016, 28, 7006–7016.

Prussian Blue Analogue-Derived Cobalt Sulfide Nanoparticles Embedded in N/S-Codoped Carbon Frameworks as a High-Performance Anode Material for Sodium-Ion Batteries

Metal sulfides display considerable theoretical capacities as anode materials in sodium-ion batteries (SIBs), but their application is limited by their large volume expansion, sluggish charge-transfer kinetics, and poor cycling performances. In this study, unlike the traditional coprecipitation method to prepare the Prussian blue analogue (PBA), PBA with a tremella-like microflower structure is first synthesized by the hydrothermal method under the synergistic effect of trisodium citrate dihydrate (TSC, Na3C6H5O7·2H2O) and K3[Co(CN)6], and two kinds of cobalt sulfide nanoparticles embedded in N/S-codoped carbon frameworks (namely, Co3S4@C–N/S and Co9S8@C–N/S) are successfully synthesized by a subsequent solid sulfidation process. Herein, N/S-codoped carbon frameworks improve the electronic conductivity and provide more active sites for sodium storage. As the anode material in SIBs, the Co3S4@C–N/S 1.8-based anode exhibits an excellent initial charge/discharge specific capacity of 685.3/745.2 mAh g–1 with a high initial Coulombic efficiency of 91.97% at 0.1 A g–1 and a superior cycling performance (599.1 mAh g–1 in the 600th cycle at 1 A g–1 with a capacity retention of 89.4%). However, the Co9S8@C–N/S 1.8-based anode also delivers considerable initial Coulombic efficiency (86.1% at 0.1 A g–1) with high cycling stability (391.9 mAh g–1 even in the 1200th cycle at 2 A g–1 with a capacity retention of 78.1%). This study provides a material synthesis route for high-performance anode materials used in SIBs and other alkali metal-ion batteries.

Ball-Milled Silicon with Amorphous Al2O3/C Hybrid Coating Embedded in Graphene/Graphite Nanosheets with a Boosted Lithium Storage Capability.

Electrochemical active silicon has attracted great attention as anodes for lithium-ion batteries owing to a high theoretical capacity of 4200 mA h g-1. In this work, ball-milled silicon particles with submicron size were strategically modified with a hybrid coating of amorphous alumina and carbon, which simultaneously embedded in a porous framework of in situ exfoliated graphene/graphite nanosheets (GGN). The composite exhibits an enhanced electrochemical performance, including high cycling stability and superior rate capability. An initial discharge capacity of 1294 mA h g-1 and a reversible charge capacity of 1044 mA h g-1 at 0.2 A g-1 can be achieved with a high initial Coulombic efficiency of up to ca. 81%. Additionally, the composite can remain 902 mA h g-1 after 100 discharge/charge cycles, accounting for a high retention of about 86%. This silicon composite is a promising anode material for high performance lithium-ion batteries with a high energy density, and the facile one-pot fabrication route is low cost and scalable, with a great prospect for practical application.

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.