Energy production and storage technologies have attracted a great deal of attention for day-to-day applications. In recent decades, advances in lithium-ion battery (LIB) technology have improved living conditions around the globe. LIBs are used in most mobile electronic devices as well as in zero-emission electronic vehicles. However, there are increasing concerns regarding load leveling of renewable energy sources and the smart grid as well as the sustainability of lithium sources due to their limited availability and consequent expected price increase. Therefore, whether LIBs alone can satisfy the rising demand for small- and/or mid-to-large-format energy storage applications remains unclear. To mitigate these issues, recent research has focused on alternative energy storage systems. Sodium-ion batteries (SIBs) are considered as the best candidate power sources because sodium is widely available and exhibits similar chemistry to that of LIBs; therefore, SIBs are promising next-generation alternatives. Recently, sodiated layer transition metal oxides, phosphates and organic compounds have been introduced as cathode materials for SIBs. Simultaneously, recent developments have been facilitated by the use of select carbonaceous materials, transition metal oxides (or sulfides), and intermetallic and organic compounds as anodes for SIBs. Apart from electrode materials, suitable electrolytes, additives, and binders are equally important for the development of practical SIBs. Despite developments in electrode materials and other components, there remain several challenges, including cell design and electrode balancing, in the application of sodium ion cells. In this article, we summarize and discuss current research on materials and propose future directions for SIBs. This will provide important insights into scientific and practical issues in the development of SIBs.

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Sodium-ion batteries: present and future

Metal Oxides and Oxysalts as Anode Materials for Li Ion Batteries

Supercapacitors have drawn considerable attention in recent years due to their high specific power, long cycle life, and ability to bridge the power/energy gap between conventional capacitors and batteries/fuel cells. Nanostructured electrode materials have demonstrated superior electrochemical properties in producing high-performance supercapacitors. In this review article, we describe the recent progress and advances in designing nanostructured supercapacitor electrode materials based on various dimensions ranging from zero to three. We highlight the effect of nanostructures on the properties of supercapacitors including specific capacitance, rate capability and cycle stability, which may serve as a guideline for the next generation of supercapacitor electrode design.

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Supercapacitor electrode materials: nanostructures from 0 to 3 dimensions

Hierarchical porous nitrogen-doped carbon (HPNC) nanosheets (NS) have been prepared via simultaneous activation and graphitization of biomass-derived natural silk. The as-obtained HPNC-NS show favorable features for electrochemical energy storage such as high specific surface area (SBET: 2494 m2/g), high volume of hierarchical pores (2.28 cm3/g), nanosheet structures, rich N-doping (4.7%), and defects. With respect to the multiple synergistic effects of these features, a lithium-ion battery anode and a two-electrode-based supercapacitor have been prepared. A reversible lithium storage capacity of 1865 mA h/g has been reported, which is the highest for N-doped carbon anode materials to the best of our knowledge. The HPNC-NS supercapacitor’s electrode in ionic liquid electrolytes exhibit a capacitance of 242 F/g and energy density of 102 W h/kg (48 W h/L), with high cycling life stability (9% loss after 10 000 cycles). Thus, a high-performance Li-ion battery and supercapacitors were successfully assembled f...

Hierarchical Porous Nitrogen-Doped Carbon Nanosheets Derived from Silk for Ultrahigh-Capacity Battery Anodes and Supercapacitors

Nitrogen-doped graphene can be used for lithium storage, but the nitrogen content is often quite low. Here, the authors synthesize graphene analogous with high nitrogen content using a zeolitic imidazolate framework, which show exceptional battery performances.

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High lithium anodic performance of highly nitrogen-doped porous carbon prepared from a metal-organic framework

Nitrogen-doped carbon nanofiber webs (CNFWs) with high surface areas are successfully prepared by carbonization-activation of polypyrrole nanofiber webs with KOH. The as-obtained CNFWs exhibit a superhigh reversible capacity of 943 mAh g(-1) at a current density of 2 A g(-1) even after 600 cycles, which is ascribed to the novel porous nanostructure and high-level nitrogen doping.

Nitrogen‐Doped Porous Carbon Nanofiber Webs as Anodes for Lithium Ion Batteries with a Superhigh Capacity and Rate Capability

Functionalized three-dimensional hierarchical porous carbon (THPC) is prepared via a facile modified chemical activation route with polypyrrole microsheets as precursor and KOH as activating agent. The as-obtained THPC presents a large specific surface area (2870 m2 g−1), high-level heteroatom doping (N: 7.7 wt%, O: 12.4 wt%), excellent electrical conductivity (5.6 S cm−1), and hierarchical porous nano-architecture containing macroporous frameworks, mesoporous walls and microporous textures. Such unique features make the THPC an ideal electrode material for electrochemical energy storage. As the electrode material for a supercapacitor, the THPC exhibits a high capacitance, excellent rate performance and long-term stability in both aqueous and organic electrolytes.

Synthesis of functionalized 3D hierarchical porous carbon for high-performance supercapacitors

S-doped carbon is investigated as a high-performance anode material for sodium-ion batteries. Due to the introduction of a high-content of S atoms, the as-obtained S-doped carbon shows an enlarged interlayer distance. As an anode, a high specific capacity of up to 303 mAh g-1 is achieved, even after 700 cycles at 0.5 A g-1.

Sulfur-Doped Carbon with Enlarged Interlayer Distance as a High-Performance Anode Material for Sodium-Ion Batteries.

Superior lithium storage performance in nanoscaled MnO promoted by N-doped carbon webs

Oxygen-rich carbon material is successfully fabricated from a porous carbon and evaluated as anode for sodium-ion battery. With the strategy of optimal combination of fast surface redox reaction and reversible intercalation, the oxygen-rich carbon anode exhibits a large reversible capacity (447 mAh g-1 at 0.2 A g-1), high rate capability (172 mAh g-1 at 20 A g-1), and excellent cycling stability.

https://www.onlinelibrary.wiley.com/doi/epdf/10.1002/advs.201600500

Wei-Min Chen

Papers

Nitrogen‐Doped Porous Carbon Nanofiber Webs as Anodes for Lithium Ion Batteries with a Superhigh Capacity and Rate Capability

Synthesis of functionalized 3D hierarchical porous carbon for high-performance supercapacitors

Sulfur-Doped Carbon with Enlarged Interlayer Distance as a High-Performance Anode Material for Sodium-Ion Batteries.

Superior lithium storage performance in nanoscaled MnO promoted by N-doped carbon webs

Coordination of Surface-Induced Reaction and Intercalation: Toward a High-Performance Carbon Anode for Sodium-Ion Batteries.