Li‐rich cathode materials have attracted increasing attention because of their high reversible discharge capacity (>250 mA h g−1), which originates from transition metal (TM) ion redox reactions and ...unconventional oxygen anion redox reactions. However, many issues need to be addressed before their practical applications, such as their low kinetic properties and inefficient voltage fading. The development of cutting‐edge technologies has led to cognitive advances in theory and offer potential solutions to these problems. Herein, a recent in‐depth understanding of the mechanisms and the frontier electrochemical research progress of Li‐rich cathodes are reviewed. In addition, recent advances associated with various strategies to promote the performance and the development of modification methods are discussed. In particular, excluding Li‐rich Mn‐based (LRM) cathodes, other branches of the Li‐rich cathode materials are also summarized. The consistent pursuit is to obtain energy storage devices with high capacity, reliable practicability, and absolute safety. The recent literature and ongoing efforts in this area are also described, which will create more opportunities and new ideas for the future development of Li‐rich cathode materials.
The practical applications of Li‐rich cathode materials, especially Li‐rich Mn‐based (LRM) cathodes, are hindered by their inherent shortcomings. In this case, the recent understanding of complex reaction mechanisms, the novel modification methods, and the corresponding development trends are comprehensively reviewed. Additionally, other branches and the future opportunities of the Li‐rich cathode materials are also summarized.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Lithium–sulfur (Li–S) batteries are regarded as the most promising next‐generation energy storage systems due to their high energy density and cost‐effectiveness. However, their practical ...applications are seriously hindered by several inevitable drawbacks, especially the shuttle effects of soluble lithium polysulfides (LiPSs) which lead to rapid capacity decay and short cycling lifespan. This review specifically concentrates on the shuttle path of LiPSs and their interaction with the corresponding cell components along the moving way, systematically retrospect the recent advances and strategies toward polysulfides diffusion suppression. Overall, the strategies for the shuttle effect inhibition can be classified into four parts, including capturing the LiPSs in the sulfur cathode, reducing the dissolution in electrolytes, blocking the shuttle channels by functional separators, and preventing the chemical reaction between LiPSs and Li metal anode. Herein, the fundamental aspect of Li–S batteries is introduced first to give an in‐deep understanding of the generation and shuttle effect of LiPSs. Then, the corresponding strategies toward LiPSs shuttle inhibition along the diffusion path are discussed step by step. Finally, general conclusions and perspectives for future research on shuttle issues and practical application of Li–S batteries are proposed.
This review summarizes the recent advances and strategies to suppress the shuttle effect of lithium polysulfides (LiPSs) in lithium–sulfur batteries. These strategies are composed of using the modified sulfur hosts to immobilize LiPSs, electrolyte systems to alleviate shuttle behavior, functional separator to intercept LiPSs, and anode surface engineering to avoid the chemical reaction between LiPSs and Li.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Sodium metal batteries are arousing extensive interest owing to their high energy density, low cost and wide resource. However, the practical development of sodium metal batteries is inherently ...plagued by the severe volume expansion and the dendrite growth of sodium metal anode during long cycles under high current density. Herein, a simple electrospinning method is applied to construct the uniformly nitrogen-doped porous carbon fiber skeleton and used as three-dimensional (3D) current collector for sodium metal anode, which has high specific surface area (1,098 m
2
/g) and strong binding to sodium metal. As a result, nitrogen-doped carbon fiber current collector shows a low sodium deposition overpotential and a highly stable cyclability for 3,500 h with a high coulombic effciency of 99.9% at 2 mA/cm
2
and 2 mAh/cm
2
. Moreover, the full cells using carbon coated sodium vanadium phosphate as cathode and sodium pre-plated nitrogen-doped carbon fiber skeleton as hybrid anode can stably cycle for 300 times. These results illustrate an effective strategy to construct a 3D uniformly nitrogen-doped carbon skeleton based sodium metal hybrid anode without the formation of dendrites, which provide a prospect for further development and research of high performance sodium metal batteries.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
With its high theoretical capacity, lithium (Li) metal is recognized as the most potential anode for realizing a high‐performance energy storage system. A series of questions (severe safety hazard, ...low Coulombic efficiency, short lifetime, etc.) induced by uncontrollable dendrites growth, unstable solid electrolyte interface layer, and large volume change, make practical application of Li‐metal anodes still a threshold. Due to their highly appealing properties, carbon‐based materials as hosts to composite with Li metal have been passionately investigated for improving the performance of Li‐metal batteries. This review displays an overview of the critical role of carbon‐based hosts for improving the comprehensive performance of Li‐metal anodes. Based on correlated mainstream models, the main failure mechanism of Li‐metal anodes is introduced. The advantages and strategies of carbon‐based hosts to address the corresponding challenges are generalized. The unique function, existing limitation, and recent research progress of key carbon‐based host materials for Li‐metal anodes are reviewed. Finally, a conclusion and an outlook for future research of carbon‐based hosts are presented. This review is dedicated to summarizing the advances of carbon‐based materials hosts in recent years and providing a reference for the further development of carbon‐based hosts for advanced Li‐metal anodes.
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Carbon‐based hosts are of great significance for the future development of high‐performance Li‐metal anodes. This review summarizes the recent developments of carbon‐based hosts for Li‐metal accommodation. The carbon‐based hosts with high surface area and conductivity can suppress dendrites growth, relieve volume expansion, and stabilize interface, and further doping and compositing to the hosts can effectively regulate Li plating/stripping behaviors.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Highlights
A bi-service host with lithiophilic/sulfiphilic Fe
2
CoSe
4
quantum dots embedded in three-dimensional ordered nitrogen-doped carbon skeleton is elaborately developed for both the sulfur ...cathode and Li anode synchronously.
The highly dispersed Fe
2
CoSe
4
quantum dots can not only act as a redox accelerator to promote the bidirectional conversion of LiPSs but also regulate the uniform Li plating/stripping to mitigate the growth of Li dendrite.
The assembled Li-S full batteries achieve excellent long-term cyclability and a remarkable areal capacity of 8.41 mAh cm
2
at high sulfur loading of 8.50 mg cm
2
, and the pouch full battery also displays high capacity and cycling-stability at lean electrolyte condition.
The commercial viability of lithium–sulfur batteries is still challenged by the notorious lithium polysulfides (LiPSs) shuttle effect on the sulfur cathode and uncontrollable Li dendrites growth on the Li anode. Herein, a bi-service host with Co-Fe binary-metal selenide quantum dots embedded in three-dimensional inverse opal structured nitrogen-doped carbon skeleton (3DIO FCSe-QDs@NC) is elaborately designed for both sulfur cathode and Li metal anode. The highly dispersed FCSe-QDs with superb adsorptive-catalytic properties can effectively immobilize the soluble LiPSs and improve diffusion-conversion kinetics to mitigate the polysulfide-shutting behaviors. Simultaneously, the 3D-ordered porous networks integrated with abundant lithophilic sites can accomplish uniform Li deposition and homogeneous Li-ion flux for suppressing the growth of dendrites. Taking advantage of these merits, the assembled Li–S full batteries with 3DIO FCSe-QDs@NC host exhibit excellent rate performance and stable cycling ability (a low decay rate of 0.014% over 2,000 cycles at 2C). Remarkably, a promising areal capacity of 8.41 mAh cm
−2
can be achieved at the sulfur loading up to 8.50 mg cm
−2
with an ultra-low electrolyte/sulfur ratio of 4.1 μL mg
−1
. This work paves the bi-serve host design from systematic experimental and theoretical analysis, which provides a viable avenue to solve the challenges of both sulfur and Li electrodes for practical Li–S full batteries.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
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•Co2P-Co hollow nanospheres with graphene sheets decoration are prepared through one-pot solution approach.•Co2P-Co/graphene nanocomposites reveal greatly enhanced lithium storage ...performances than Co2P-Co counterparts.•The superb electrochemical performances derive from dual modification of graphene sheets and metal Co as well as their hollow configuration.
The fabrication of Co2P-Co (Co-P composites) hollow nanospheres with graphene sheets decoration through one-pot solution approach is demonstrated and their potential as the anode materials for lithium ion batteries is assessed. A large specific capacity of 929mAhg−1 can be retained for Co-P/graphene nanocomposites at 100mAg−1 after 200 cycles. When cycled at a large current density of 2.0C, the Co-P/graphene nanocomposites deliver a decent reversible capacity of 567mAhg−1, which is much higher than the theoretical capacity of traditional graphite anode (372mAhg−1). The obviously enhanced lithium storage properties of Co-P/graphene nanocomposites are put down to the dual modification of graphene sheets and metal Co as well as their hollow structures.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK, ZRSKP
Highlights
A novel three-in-one method is put forward to prepare Li- and Mn-rich cathode.
The stress evolution of layered materials during cycling is characterized.
The capacity and voltage stability ...are enhanced greatly.
There are plenty of issues need to be solved before the practical application of Li- and Mn-rich cathodes, including the detrimental voltage decay and mediocre rate capability, etc. Element doping can effectively solve the above problems, but cause the loss of capacity. The introduction of appropriate defects can compensate the capacity loss; however, it will lead to structural mismatch and stress accumulation. Herein, a three-in-one method that combines cation–polyanion co-doping, defect construction, and stress engineering is proposed. The co-doped Na
+
/SO
4
2−
can stabilize the layer framework and enhance the capacity and voltage stability. The induced defects would activate more reaction sites and promote the electrochemical performance. Meanwhile, the unique alternately distributed defect bands and crystal bands structure can alleviate the stress accumulation caused by changes of cell parameters upon cycling. Consequently, the modified sample retains a capacity of 273 mAh g
−1
with a high-capacity retention of 94.1% after 100 cycles at 0.2 C, and 152 mAh g
−1
after 1000 cycles at 2 C, the corresponding voltage attenuation is less than 0.907 mV per cycle.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Li-rich Mn-based layered oxide cathodes (LLOs), delivering high specific capacity of >300 mAh g−1 and maximum energy density of >1000 Wh kg−1, are deemed to be one of the most promising cathode ...candidates for next-generation lithium-ion batteries over 350 Wh kg−1 at the full cell level. However, the practical application of LLOs is still hindered by two main challenges: microcosmic material drawbacks (structural instability, poor diffusion kinetics, etc.) and thus induced macroscopic decay of electrochemical performance (low initial Coulombic efficiency, fast capacity/voltage decay, etc.). In this review, we summarize the current developments of LLOs in the structure, corresponding reaction mechanisms, and electrochemical performances, discuss the relationship between inherent material drawbacks and external performance decay, as well as summarize the performance degradation mechanisms and addressing strategies to provide guidance and perspectives for future LLOs research.
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•Current advancements in crystal structure, electrochemical redox mechanisms, and electrochemical performance are presented.•The complex relationships between inherent material drawbacks and external performance degradation are revealed.•Current strategies and possible solutions in the future are summarized.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
The corrosion of Li‐ and Mn‐rich (LMR) electrode materials occurring at the solid–liquid interface will lead to extra electrolyte consumption and transition metal ions dissolution, causing rapid ...voltage decay, capacity fading, and detrimental structure transformation. Herein, a novel strategy is introduced to suppress this corrosion by designing an Na+‐doped LMR (Li1.2Ni0.13Co0.13Mn0.54O2) with abundant stacking faults, using sodium dodecyl sulfate as surfactant to ensure the uniform distribution of Na+ in deep grain lattices—not just surface‐gathering or partially coated. The defective structure and deep distribution of Na+ are verified by Raman spectrum and high‐resolution transmission electron microscopy of the as‐prepared electrodes before and after 200 cycles. As a result, the modified LMR material shows a high reversible discharge specific capacity of 221.5 mAh g−1 at 0.5C rate (1C = 200 mA g−1) after 200 cycles, and the capacity retention is as high as 93.1% which is better than that of pristine‐LMR (64.8%). This design of Na+ is uniformly doped and the resultanting induced defective structure provides an effective strategy to enhance electrochemical performance which should be extended to prepare other advanced cathodes for high performance lithium‐ion batteries.
The Li‐ and Mn‐rich (LMR) cathode Li1.2Ni0.13Co0.13Mn0.54O2 is doped by Na+ ions uniformly in deep grains and the resultanting induced stacking faults can also enhance electrochemical performance for lithium‐ion batteries. The modified LMR shows a high reversible discharge specifc capacity of 221.5 mAh g−1 at 0.5C rate (1C = 200 mA g−1) after 200 cycles with a capacity retention of 93.1%.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Li metal anodes are undergoing a renaissance due to their ultra-high specific capacity and the lowest reduction potential. However, the practical application of Li-metal anodes is still challenged by ...Li dendrite growth and low coulombic efficiency (CE). Herein, a gradient Si-modified carbon paper (GSCP) made
via
magnetic sputtering is proposed to address these issues, in which the content of lithiophilic Si gradually decreases from the bottom to the top of the 3D host. Such a gradient lithiophilic structure can cause the Li metal to selectively nucleate and grow at the bottom first and then to the top part of GSCP, realizing stable Li plating/stripping and high space utilization of the 3D host simultaneously. Therefore, the designed GSCP composite anode achieves average CEs of 99.0% (400 cycles) and 97.0% (150 cycles) at 1 and 5 mA cm
−2
, respectively, and a prolonged lifespan (1350 h) with a low overpotential (∼15 mV). Remarkably, the GSCP@Li|Li
4
Ti
5
O
12
full cell exhibits high capacity retention of 84.5% after 5000 cycles at a 10C rate.
3D gradient Si-modified carbon papers (GSCP) with good electronic conductivity and gradient lithiophilic configurations can regulate Li nucleation/growth in a bottom-up manner and endow outstanding coulombic efficiency and cyclability in full cells.
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