Rational Synthesis and Assembly of Ni 3 S 4 Nanorods for Enhanced Electrochemical Sodium-Ion Storage

Kang

et al. 2018

Advanced Science

Based on multielectron conversion reactions, layered transition metal dichalcogenides are considered promising electrode materials for sodium‐ion batteries, but suffer from poor cycling performance and rate capability due to their low intrinsic conductivity and severe volume variations. Here, interlayer‐expanded MoSe2/phosphorus‐doped carbon hybrid nanospheres coated by anatase TiO2 (denoted as MoSe2/P‐C@TiO2) are prepared by a facile hydrolysis reaction, in which TiO2 coating polypyrrole‐phosphomolybdic acid is utilized as a novel precursor followed by a selenization process. Benefiting from synergistic effects of MoSe2, phosphorus‐doped carbon, and TiO2, the hybrid nanospheres manifest unprecedented cycling stability and ultrafast pseudocapacitive sodium storage capability. The MoSe2/P‐C@TiO2 delivers decent reversible capacities of 214 mAh g−1 at 5.0 A g−1 for 8000 cycles, 154 mAh g−1 at 10.0 A g−1 for 10000 cycles, and an exceptional rate capability up to 20.0 A g−1 with a capacity of ≈175 mAh g−1 in a voltage range of 0.5–3.0 V. Coupled with a Na3V2(PO4)3@C cathode, a full cell successfully confirms a reversible capacity of 242.2 mAh g−1 at 0.5 A g−1 for 100 cycles with a coulombic efficiency over 99%.

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

TiO₂‐Coated Interlayer‐Expanded MoSe₂/Phosphorus‐Doped Carbon Nanospheres for Ultrafast and Ultralong Cycling Sodium Storage

Kang

et al. 2018

Advanced Science

“…[1][2][3][4][5][6][7][8][9][10][11] Hitherto, the commercialization of SIBs has been held back, however, by their low energy density and unsatisfactory cycle life. [1][2][3][4][5][6][7][8][9][10][11] Hitherto, the commercialization of SIBs has been held back, however, by their low energy density and unsatisfactory cycle life.…”

mentioning

confidence: 99%

Stress Distortion Restraint to Boost the Sodium Ion Storage Performance of a Novel Binary Hexacyanoferrate

Han

Advanced Energy Materials

et al. 2019

107

125

and are considered as a new generation of energy storage devices to replace lithium ion batteries (LIBs) in certain applications. [1][2][3][4][5][6][7][8][9][10][11] Hitherto, the commercialization of SIBs has been held back, however, by their low energy density and unsatisfactory cycle life. The cathode, as much as the anode, also plays an important role in the final performance of the battery. Thus, it is crucial to develop cathode candidates with both high energy density and stable cycle life for sodium ion storage.It is accepted that the energy density is determined by the specific capacity and the voltage plateau of an electrode. The commercial cathode materials for LIBs can deliver 510-700 Wh kg −1 energy density with a potential plateau of 3.4-4.1 V (3.4 V for LiFePO 4 and 4.1 V for spinel LiMn 2 O 4 ) and high specific capacity of over 150 mAh g −1 . In comparison, most of the cathode candidates reported for SIBs show a potential plateau below 3.2 V and a capacity below 110 mAh g −1 , delivering energy density lower than 350 Wh kg −1 . [12][13][14][15][16][17] Exceptionally, the sodium superionic conductor Na 3 V 2 (PO 4 ) 3 presented a 3.4 V potential plateau and 115 mAh g −1 capacity; Na 3 (VO 1−x PO 4 ) 2 F 1+2x (0 < x < 1) showed 3.8-3.9 V average voltage and 120-130 mAh g −1 capacity. [18][19][20][21][22] Honeycomb-layered Na 3 Ni 2 SbO 6 provided an average working potential at 3.3 V and a high capacity of ≈120 mAh g −1 . Moreover, Na 3 Ni 2 SbO 6 showed superior rate capability and excellent cycling performance. [23,24] In the long run, however, these cathode materials containing toxic elements (V and Sb) are not suitable for commercial SIBs because commercialization also requires electrode materials to possess the properties of environmental friendliness and low cost in addition to excellent electrochemical performance.Recently, Prussian blue analogues (PBAs) have attracted much attention owing to their low cost and environmentalfriendliness. [6,[25][26][27][28] The PBAs utilized for electrode materials can be classified into three groups, that is, hexacyanoferrates (ATFe(CN) 6 ), hexacyanomanganates (ATMn(CN) 6 ), and hexacyanocobaltates (ATCo(CN) 6 , where A = K, Na; T = Fe, Mn, Ni, Co). Among them, hexacyanoferrates, in particular, have been put under the spotlight due to their nonpoisonous raw material ferrocyanide (Na 4 Fe(CN) 6 or K 3 Fe(CN) 6 ), while the raw materials K 3 Mn(CN) 6 for hexacyanomanganate and K 3 Co(CN) 6 for hexacyanocobaltate are harmful and toxic. In the case of Mn-based hexacyanoferrate Na x MnFe(CN) 6 (NMHFC) has been attracting more attention as a promising cathode material for sodium ion storage owing to its low cost, environmental friendliness, and its high voltage plateau of 3.6 V, which comes from the Mn 2+ /Mn 3+ redox couple. In particular, the Na-rich NMHFC (x > 1.40) with trigonal phase is considered an attractive candidate due to its large capacity of ≈130 mAh g −1 , delivering high energy density. Its unstable cycle life, however, is holding back its practica...

“…Generally, favorable anode materials with long life, great cycling stability and high rate performance, are the most important factors for the commercial development of SIBs . Up to now, several materials have been devoted to improve the outstanding electrochemical properties of anode materials in SIBs, including carbon‐based materials, alloy materials and transition metal‐based materials …”

Section: Introductionmentioning

confidence: 99%

“…[15] Up to now, several materials have been devoted to improve the outstanding electrochemical properties of anode materials in SIBs, including carbon-based materials, alloy materials and transition metal-based materials. [16,17] During the past decades, a series of TMDs, such as MoS 2 , [18] WS 2 [19] and SnS 2 , [20] were received increasing attention because of their unique layered structures, higher electronic conductivity and more active sites. [21] As a representative member of TMDs family with the hexagonal system, vanadium disulfide (VS 2 ) possesses a similar layered crystal structure to MoS 2 , which is made of metal V between the two S layers to form a "SÀ VÀ S" sandwich structure.…”

Section: Introductionmentioning

confidence: 99%

Hollow Structure VS₂@Reduced Graphene Oxide (RGO) Architecture for Enhanced Sodium‐Ion Battery Performance

Zuo

et al. 2019

ChemElectroChem

As a typical two‐dimensional (2D) layered material, (vanadium disulfide) VS2 has huge potentials for application in SIBs due to its large interlayer spacing and high conductivity compared to metal oxide or other 2D materials. Reduced graphene oxide (RGO) possesses exceptional electronic properties and large specific area favoring fast electron transport and rich redox sites. In this work, VS2 hollow flower spheres and RGO nanocomposites were developed for the first time, it was synthesized using a facile solvothermal method. Benefiting from the exceptional layered structure, when used as the anode material for SIBs at room temperature, the as‐prepared electrode material of VS2 hollow flower spheres @RGO (named as VS2 HFS/RGO) nanocomposites delivers a high reversible discharge specific capacity of around 430 mAh/g at current density of 100 mA/g, superior rate performance (2 A/g) and excellent cycling properties with the discharge capacity remained 350 mAh/g at 100 mA/g after 500 cycles. Results show that the kinetics of VS2 HFS/RGO nanocomposites were mainly a capacitive‐controlled storage process and the high capacity contribution were beneficial for good rate performance. This work could provide new approaches and potentials for exploring and searching high performances anode materials for the practical applications of SIBs.