Li-ion battery materials: present and future

Lithium-ion batteries have had a profound impact on our daily life, but inherent limitations make it difficult for Li-ion chemistries to meet the growing demands for portable electronics, electric vehicles and grid-scale energy storage. Therefore, chemistries beyond Li-ion are currently being investigated and need to be made viable for commercial applications. The use of metallic Li is one of the most favoured choices for next-generation Li batteries, especially Li-S and Li-air systems. After falling into oblivion for several decades because of safety concerns, metallic Li is now ready for a revival, thanks to the development of investigative tools and nanotechnology-based solutions. In this Review, we first summarize the current understanding on Li anodes, then highlight the recent key progress in materials design and advanced characterization techniques, and finally discuss the opportunities and possible directions for future development of Li anodes in applications.

Reviving the lithium metal anode for high-energy batteries

The lithium metal battery is strongly considered to be one of the most promising candidates for high-energy-density energy storage devices in our modern and technology-based society. However, uncontrollable lithium dendrite growth induces poor cycling efficiency and severe safety concerns, dragging lithium metal batteries out of practical applications. This review presents a comprehensive overview of the lithium metal anode and its dendritic lithium growth. First, the working principles and technical challenges of a lithium metal anode are underscored. Specific attention is paid to the mechanistic understandings and quantitative models for solid electrolyte interphase (SEI) formation, lithium dendrite nucleation, and growth. On the basis of previous theoretical understanding and analysis, recently proposed strategies to suppress dendrite growth of lithium metal anode and some other metal anodes are reviewed. A section dedicated to the potential of full-cell lithium metal batteries for practical applicatio...

Toward Safe Lithium Metal Anode in Rechargeable Batteries: A Review.

Rechargeable lithium-sulfur batteries.

Due to their high energy density and low material cost, lithium–sulfur batteries represent a promising energy storage system for a multitude of emerging applications, ranging from stationary grid storage to mobile electric vehicles. This review aims to summarize major developments in the field of lithium–sulfur batteries, starting from an overview of their electrochemistry, technical challenges and potential solutions, along with some theoretical calculation results to advance our understanding of the material interactions involved. Next, we examine the most extensively-used design strategy: encapsulation of sulfur cathodes in carbon host materials. Other emerging host materials, such as polymeric and inorganic materials, are discussed as well. This is followed by a survey of novel battery configurations, including the use of lithium sulfide cathodes and lithium polysulfide catholytes, as well as recent burgeoning efforts in the modification of separators and protection of lithium metal anodes. Finally, we conclude with an outlook section to offer some insight on the future directions and prospects of lithium–sulfur batteries.

Designing high-energy lithium–sulfur batteries

Lithium dendrite growth is a serious hazard in battery operations. Here, the authors show that when using lithium polysulfide and lithium nitrate as additives in ether-based electrolyte, a stable and uniform solid electrolyte interphase forms on the lithium surface, which prevents dendrite growth.

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The synergetic effect of lithium polysulfide and lithium nitrate to prevent lithium dendrite growth

Lithium sulfur batteries have brought significant advancement to the current state-of-art battery technologies because of their high theoretical specific energy, but their wide-scale implementation has been impeded by a series of challenges, especially the dissolution of intermediate polysulfides species into the electrolyte. Conductive polymers in combination with nanostructured sulfur have attracted great interest as promising matrices for the confinement of lithium polysulfides. However, the roles of different conductive polymers on the electrochemical performances of sulfur electrode remain elusive and poorly understood due to the vastly different structural configurations of conductive polymer–sulfur composites employed in previous studies. In this work, we systematically investigate the influence of different conductive polymers on the sulfur cathode based on conductive polymer-coated hollow sulfur nanospheres with high uniformity. Three of the most well-known conductive polymers, polyaniline (PANI)...

/pdf/understanding-the-role-of-different-conductive-polymers-in-2q0t14bcze.pdf

Understanding the Role of Different Conductive Polymers in Improving the Nanostructured Sulfur Cathode Performance

Sulfur is an exciting cathode material with high specific capacity of 1,673 mAh/g, more than five times the theoretical limits of its transition metal oxides counterpart. However, successful applications of sulfur cathode have been impeded by rapid capacity fading caused by multiple mechanisms, including large volume expansion during lithiation, dissolution of intermediate polysulfides, and low ionic/electronic conductivity. Tackling the sulfur cathode problems requires a multifaceted approach, which can simultaneously address the challenges mentioned above. Herein, we present a scalable, room temperature, one-step, bottom-up approach to fabricate monodisperse polymer (polyvinylpyrrolidone)-encapsulated hollow sulfur nanospheres for sulfur cathode, allowing unprecedented control over electrode design from nanoscale to macroscale. We demonstrate high specific discharge capacities at different current rates (1,179, 1,018, and 990 mAh/g at C/10, C/5, and C/2, respectively) and excellent capacity retention of 77.6% (at C/5) and 73.4% (at C/2) after 300 and 500 cycles, respectively. Over a long-term cycling of 1,000 cycles at C/2, a capacity decay as low as 0.046% per cycle and an average coulombic efficiency of 98.5% was achieved. In addition, a simple modification on the sulfur nanosphere surface with a layer of conducting polymer, poly(3,4-ethylenedioxythiophene), allows the sulfur cathode to achieve excellent high-rate capability, showing a high reversible capacity of 849 and 610 mAh/g at 2C and 4C, respectively.

https://www.pnas.org/content/pnas/110/18/7148.full.pdf

High-performance hollow sulfur nanostructured battery cathode through a scalable, room temperature, one-step, bottom-up approach

Pillared MXene with Ultralarge Interlayer Spacing as a Stable Matrix for High Performance Sodium Metal Anodes

Sodium (Na) metal has shown great promise as an anode material for the next-generation energy storage systems because of its high theoretical capacity, low cost, and high earth abundance. However, the extremely high reactivity of Na metal with organic electrolyte leads to the formation of unstable solid electrolyte interphase (SEI) and growth of Na dendrites upon repeated electrochemical stripping/plating, causing poor cycling performance, and serious safety issues. Herein, we present highly stable and dendrite-free Na metal anodes over a wide current range and long-term cycling via directly applying free-standing graphene films with tunable thickness on Na metal surface. We systematically investigate the dependence of Na anode stability on the thickness of the graphene film at different current densities and capacities. Our findings reveal that only a few nanometer (∼2–3 nm) differences in the graphene thickness can have decisive influence on the stability and rate capability of Na anodes. To achieve the...

Weiyang Li

Papers

The synergetic effect of lithium polysulfide and lithium nitrate to prevent lithium dendrite growth

Understanding the Role of Different Conductive Polymers in Improving the Nanostructured Sulfur Cathode Performance

High-performance hollow sulfur nanostructured battery cathode through a scalable, room temperature, one-step, bottom-up approach

Pillared MXene with Ultralarge Interlayer Spacing as a Stable Matrix for High Performance Sodium Metal Anodes

Critical Role of Ultrathin Graphene Films with Tunable Thickness in Enabling Highly Stable Sodium Metal Anodes.