Dual‐ion batteries (DIBs) have attracted much attention owing to their low cost, high voltage, and environmental friendliness. As the source of active ions during the charging/discharging process, ...the electrolyte plays a critical role in the performance of DIBs, including capacity, energy density, and cycling life. However, most used electrolyte systems based on the LiPF6 salt demonstrate unsatisfactory performance in DIBs. We have successfully developed a 7.5 mol kg−1 lithium bis(fluorosulfonyl)imide (LiFSI) in a carbonate electrolyte system. Compared with diluted electrolytes, this highly concentrated electrolyte exhibits several advantages: 1) enhanced intercalation capacity and cycling stability of the graphite cathode, 2) optimized structural stability of the Al anode, and 3) significantly increased battery energy density. A proof‐of‐concept DIB based on this concentrated electrolyte exhibits a discharge capacity of 94.0 mAh g−1 at 200 mA g−1 and 96.8 % capacity retention after 500 cycles. By counting both the electrode materials and electrolyte, the energy density of this DIB reaches up to ≈180 Wh kg−1, which is among the best performances of DIBs reported to date.
A 7.5 mol kg−1 LiFSI highly concentrated electrolyte was developed for a dual‐ion battery (DIB). A proof‐of‐concept DIB based on this concentrated electrolyte exhibits a discharge capacity of 94.0 mAh g−1 at 200 mA g−1, 96.8 % capacity retention after 500 cycles, and an energy density up to approximately 180 Wh kg−1 based on the electrode materials and electrolyte, which is among the best performances of previously reported DIBs.
A novel battery configuration based on an aluminum foil anode and a conventional cathode is developed. The aluminum foil plays a dual role as both the active anode material and the current collector, ...which enhances the energy density of the packaged battery, and reduces the production cost. This generalized battery configuration has high potential for application in next‐generation lithium‐ion batteries.
Dual‐ion batteries (DIBs) have attracted increasing attention due to their high working voltage, low cost, and environmental friendliness, yet their development is hindered by their limited energy ...density. Pairing silicon—a most promising anode due to its highest theoretical capacity (4200 mAh g−1)—with a graphite cathode is a feasible strategy to address the challenge. Nevertheless, the cycling stability of silicon is unsatisfactory due to the loss of electrical contact resulting from the high interface stress when using rigid current collectors. In this work, a flexible interface design to regulate the stress distribution is proposed, via the construction of a silicon anode on a soft nylon fabric modified with a conductive Cu–Ni transition layer, which endows the silicon electrode with remarkable flexibility and stability over 50 000 bends. Assembly of the flexible silicon anode with an expanded graphite cathode yields a silicon–graphite DIB (SGDIB), which possesses record‐breaking rate performance (up to 150 C) and cycling stability over 2000 cycles at 10 C with a capacity retention of 97%. Moreover, the SGDIB shows a high capacity retention of ≈84% after 1500 bends and a low self‐discharging voltage loss of 0.0015% per bend after 10 000 bends, suggesting high potential for high‐performance flexible energy‐storage applications.
A flexible interface design to regulate stress is demonstrated via constructing a silicon anode on an elastic fabric with a conductive buffer layer. A novel silicon–graphite dual‐ion battery concept is established via combining the flexible silicon anode with an expanded graphite cathode, which exhibits excellent electrochemical performance with a capacity retention of 97% over 2000 cycles at 10 C.
Aluminum (Al) is one of the most attractive anode materials for lithium‐ion batteries (LIBs) due to its high theoretical specific capacity, excellent conductivity, abundance, and especially low cost. ...However, the large volume expansion, originating from the uneven alloying/dealloying reactions in the charge/discharge process, causes structural stress and electrode pulverization, which has long hindered its practical application, especially when assembled with a high‐areal‐density cathode. Here, an inactive (Cu) and active (Al) co‐deposition strategy is reported to homogeneously distribute the alloying sites and disperse the stress of volume expansion, which is beneficial to obtain the structural stability of the Al anode. Owing to the homogeneous reaction and uniform distribution of stress during the charge/discharge process, the assembled full battery (LiFePO4 cathode with a high areal density of ≈7.4 mg cm−2) with the Cu–Al@Al anode, achieves a high capacity retention of ≈88% over 200 cycles, suggesting the feasibility of the interfacial design to optimize the structural stability of alloying metal anodes for high‐performance LIBs.
An inactive–active co‐deposition strategy is reported to homogeneously distribute the alloying sites and disperse the stress of volume expansion, which is beneficial to obtain the structural stability of the Al anode. Owing to the homogeneous reaction and uniform distribution of stress during charge/discharge process, a good cycling stability is achieved in high‐areal‐density lithium‐ion batteries.
Vast bulk recombination of photo-generated carriers and sluggish surface oxygen evolution reaction (OER) kinetics severely hinder the development of photoelectrochemical water splitting. Herein, ...through constructing a vertically ordered ZnInS nanosheet array with an interior gradient energy band as photoanode, the bulk recombination of photogenerated carriers decreases greatly. We use the atomic layer deposition technology to introduce Fe-In-S clusters into the surface of photoanode. First-principles calculations and comprehensive characterizations indicate that these clusters effectively lower the electrochemical reaction barrier on the photoanode surface and promote the surface OER reaction kinetics through precisely affecting the second and third steps (forming processes of O* and OOH*) of the four-electron reaction. As a result, the optimal photoanode exhibits the high performance with a significantly enhanced photocurrent of 5.35 mA cm
at 1.23 V
and onset potential of 0.09 V
. Present results demonstrate a robust platform for controllable surface modification, nanofabrication, and carrier transport.
As the incremental deficiency of Li resources, it is significant and instant to supersede Li with other earth-abundant elements for electrochemical energy storage (EES) devices. Accordingly, Na/K-ion ...energy storage devices, including rechargeable batteries and ionic capacitors with similar energy storage mechanisms to Li-ion devices, have attracted widespread concerns due to the abundant reserves of Na/K and low cost. Meanwhile, electrolytes are one of the significant hotspots to promote the comprehensive electrochemical performances of these devices. However, compared to electrode materials, insights into electrolytes in these devices are still in its infancy, leading to an inherent restriction on their performance enhancement. In this review, a brief introduction of advanced analysis and characterization technologies for electrolytes is discussed, and recent applications of various electrolytes including organic, aqueous, ionic liquid, and solid-state electrolytes for rechargeable batteries and ionic capacitors based Na/K-ion devices are also summarized. Finally, the remaining challenges and future research orientations are identified and proposed. It is hoped that this report will promote the commercial application of EES devices based on Na/K in the post lithium era.
Highlights
The development history and the reaction mechanisms involved in dual-ion batteries (DIBs) are reviewed.
The optimization strategies toward DIB electrodes and electrolytes and their ...energy-related applications are highlighted.
The research challenges and possible development directions of DIBs are outlined.
There has been increasing demand for high-energy density and long-cycle life rechargeable batteries to satisfy the ever-growing requirements for next-generation energy storage systems. Among all available candidates, dual-ion batteries (DIBs) have drawn tremendous attention in the past few years from both academic and industrial battery communities because of their fascinating advantages of high working voltage, excellent safety, and environmental friendliness. However, the dynamic imbalance between the electrodes and the mismatch of traditional electrolyte systems remain elusive. To fully employ the advantages of DIBs, the overall optimization of anode materials, cathode materials, and compatible electrolyte systems is urgently needed. Here, we review the development history and the reaction mechanisms involved in DIBs. Afterward, the optimization strategies toward DIB materials and electrolytes are highlighted. In addition, their energy-related applications are also provided. Lastly, the research challenges and possible development directions of DIBs are outlined.
Sodium‐ion batteries (NIBs) are the most promising alternatives to lithium‐ion batteries in the development of renewable energy sources. The advancement of NIBs depends on the exploration of new ...electrode materials and fundamental understanding of working mechanisms. Herein, via experimental and simulation methods, we develop a mixed polyanionic compound, Na2Fe(C2O4)SO4⋅H2O, as a cathode for NIBs. Thanks to its rigid three dimensional framework and the combined inductive effects from oxalate and sulfate, it delivered reversible Na insertion/desertion at average discharging voltages of 3.5 and 3.1 V for 500 cycles with Coulombic efficiencies of ca. 99 %. In situ synchrotron X‐ray measurements and DFT calculations demonstrate the Fe2+/Fe3+ redox reactions contribute to electron compensation during Na+ desertion/insertion. The study suggests mixed polyanionic frameworks may provide promising materials for Na ion storage with the merits of low cost and environmental friendliness.
Mixed and matched: A combined oxalate and sulfate cathode is prepared. The optimized sodium‐ion battery achieves reversible Na‐ion storage for 500 cycles with high Coulombic efficiencies of approximately 99 %, indicating that mixed polyanionic frameworks may provide promising materials for Na‐ion storage with the merits of low cost and environmental friendly.
Sodium is abundant on Earth and has similar chemical properties to lithium, thus sodium‐ion batteries (SIBs) have been considered as one of the most promising alternative energy storage systems to ...lithium‐ion batteries (LIBs). Meanwhile, a new energy storage device called sodium dual‐ion batteries (SDIBs) is attracting much attention due to its high voltage platform, low production cost, and environmental benignity coming from the feature of directly using graphite as the cathode. However, due to the large mass and ionic radius of sodium atoms, SIBs and SDIBs exhibit low energy density and inferior cycling life than LIBs. Over the past few years, tremendous efforts, especially in the area of anode materials, have been made to improve the electrochemical performance of SIBs and SDIBs. Reviewing and summarizing the previous studies will be helpful for future exploration and optimization. Herein, the recent progress on anode materials for SIBs and SDIBs is summarized according to the reaction mechanism. The structural design, reaction mechanism, and electrochemical performance of the anode materials are briefly discussed. In addition, the fundamental challenges, potential solutions, and perspectives in this field are also proposed. It is hoped that this Review may advance the development of anode materials for sodium storage.
The recent progress on anode materials for both sodium‐ion batteries and sodium dual‐ion batteries are summarized according to the different sodium storage mechanisms. The structural design, reaction mechanism, and electrochemical performance of the anode materials are briefly discussed. In addition, the fundamental challenges, potential solutions, and perspectives in this field are also presented.
PDF
