A Stable Layered Oxide Cathode Material for High‐Performance Sodium‐Ion Battery

Abstract

great significance to develop electrochemical energy-storage technique and take advantage of sustainable and renewable energy. [1][2][3][4][5][6][7] Owing to natural abundance, wide availability, and low cost of sodium resources, sodium-ion batteries (SIBs) have been considered as one of most fascinating alternatives to the well-commercialized lithium-ion batteries for future large-scale stationary energy-storage systems with high adaptability and energy efficiency. [8][9][10][11][12][13] To develop satisfactory electrode materials in the future development of SIBs, continued research efforts have been devoted to screen new cathodes over the past few years. [14][15][16][17][18][19] Among a wide variety of cathode candidates including layered oxides, polyanion compounds, and Prussian blue analogues, layered oxide cathode materials have received significant attention because of the high voltage, low cost, and simple synthesis. Recently, research has made dramatic progress especially on manganese-based layered oxides such as zinc-doped Na 0.833 [Li 0.25 Mn 0.75 ]O 2 , Na 0.7 Mg 0.05 [Mn 0.6 Ni 0.2 Mg 0.15 ]O 2 , and Na 2.3 Cu 1.1 Mn 2 O 7−δ , which open new opportunities for developing high-performance cathode materials. [20][21][22][23][24] However, typical P2-type Na 2/3 Ni 1/3 Mn 2/3 O 2 cathode material As one of the most promising cathode candidates for room-temperature sodium-ion batteries (SIBs), P2-type layered oxides face the challenge of simultaneously realizing high-rate performance while achieving long cycle life. Here, a stable Na 2/3 Ni 1/6 Mn 2/3 Cu 1/9 Mg 1/18 O 2 cathode material is proposed that consists of multiple-layer oriented stacking nanoflakes, in which the nickel sites are partially substituted by copper and magnesium, a characteristic of the material that is confirmed by multiscale scanning transmission electron microscopy and electron energy loss spectroscopy techniques. Owing to the optimal morphology structure modulation and chemical element substitution strategy, the electrode displays remarkable rate performance (73% capacity retention at 30C compared to 0.5C) and outstanding cycling stability in Na half-cell system couple with unprecedented full battery performance. The underlying thermal stability, phase stability, and Na + storage mechanisms are clearly elucidated through the systematical characterizations of electrochemical behaviors, in situ X-ray diffraction at different temperatures, and operando X-ray diffraction upon Na + deintercalation/intercalation. Surprisingly, a quasi-solid-solution reaction is switched to an absolute solid-solution reaction and a capacitive Na + storage mechanism is demonstrated via quantitative electrochemical kinetics calculation during charge/discharge process. Such a simple and effective strategy might reveal a new avenue into the rational design of excellent rate capability and long cycle stability cathode materials for practical SIBs.

Deciphering an Abnormal Layered‐Tunnel Heterostructure Induced by Chemical Substitution for the Sodium Oxide Cathode

“…Hard carbon anode without the pre-sodiation process is difficult to achieve excellent cycle stability when matched with cathode in full-cell system due to the formation of the solid electrolyte interphase (SEI) layer forming on the anode surface. [19] Hence,b efore assembling the full battery,t he pre-sodiation process of the hard carbon anode was conducted (Figure 5a;S upporting Information, Figure S21). Thef ull cell delivers high reversible specific capacity of 171.6 mAh g À1 with specific energy of 453.9 Wh kg À1 at 0.2 C ( Figure 5b;S upporting Information, Figure S22).…”

State-of-the-Art Electrode Materials for Sodium-Ion Batteries

“…When cycled between 2.5 and 4.2 V at 1C rate, this cathode demonstrated a capacity of 70 mA•h•g −1 , with 79% capacity retention after 1000 cycles. Na 2/3 Ni 1/6 Mn 2/3 Cu 1/9 Mg 1/18 O 2 cathode material consisting of multiple-layer oriented stacking nanoflakes was proposed by Xiao et al [74]. This cathode material demonstrated a good rate capability (64.0 mA•h•g −1 and 11.4 kW•kg −1 at 30C).…”

In‐Situ Fabrication of Bone‐Like CoSe2 Nano‐Thorn Loaded on Porous Carbon Cloth as a Flexible Electrode for Na‐Ion Storage

“…[1][2][3] Although the ion storage mechanism of SIBs is similar to lithium ion batteries (LIBs), [4] fallaciously, a large proportion of electrode materials recently available for LIBs is not suitable for SIBs, owing to the larger ionic radium of Na + (1 .02 Å) than that of Li + (~0.76 Å). [5,6] Furthermore, the relatively low energy density is also an urgent issue for Na-ion storage devices. [7,8] Therefore, constant exploration and rational design are stimulating intensive studies on appropriate anode materials with impressive Na-ion storage capabilities.…”