Liang-Xin Ding

Honeycomb-like NiMoO4 ultrathin nanosheet arrays for high-performance electrochemical energy storage

Supercapacitors and Li-ion batteries are two types of electrical energy storage devices. To satisfy the increasing demand for high-performance energy storage devices, traditional electrode materials, such as transition metal oxides, conducting polymers and carbon-based materials, have been widely explored. However, the results obtained to date remain unsatisfactory, and the development of inexpensive electrode materials (especially for commercial manufacturing) with superior electrochemical performance for use in supercapacitors and in Li-ion batteries is still needed. The as-prepared NiMoO4 nanosheets (NSs) with interconnecting nanoscale pore channels and an ultrathin structure provide a large electrochemical active area, which facilitates electrolyte immersion and ion transport and provides effective pathways for electron transport. Therefore, the as-prepared NiMoO4 NS electrode exhibits a high specific capacity and an excellent rate capability and cycling stability in supercapacitors and in Li-ion batteries. Moreover, a high energy density (43.5 W h kg−1 at 500 W kg−1) was obtained for the symmetric supercapacitor (SSC) composed of two sections of NiMoO4 NSs.

Freestanding, Hydrophilic Nitrogen-Doped Carbon Foams for Highly Compressible All Solid-State Supercapacitors

Freestanding and highly compressible nitrogen-doped carbon foam (NCF) with excellent hydrophilicity and good electrochemical properties is prepared. Based on NCF electrodes, a high-performance all solid-state symmetric supercapacitor device is fabricated with native, full compressibility, and excellent mechanical stability, addressing two major problems in the current technology.

Graphene-based nitrogen-doped carbon sandwich nanosheets: a new capacitive process controlled anode material for high-performance sodium-ion batteries

Anode materials with capacitive charge storage (CCS) are highly desirable for the development of high-performance sodium-ion batteries (SIBs), because the capacitive process usually shows kinetically high ion diffusion and superior structural stability. Here, we report a new CCS anode material of graphene-based nitrogen-doped carbon sandwich nanosheets (G-NCs). The as-prepared G-NCs show a high capacitive contribution during the discharge/charge processes. As expected, the G-NCs exhibit excellent rate performance with a reversible capacity of 110 mA h g−1, even at a current as high as 10000 mA g−1, and outstanding cycle stability (a retention of 154 mA h g−1 after 10000 cycles at 5000 mA g−1). This represents the best cycle stability among all reported carbon anode materials for SIBs, thereby showing great potential as a commercial anode material for SIBs.

Ultrathin and highly-ordered CoO nanosheet arrays for lithium-ion batteries with high cycle stability and rate capability

Ultrathin and highly-ordered 2D CoO nanosheet arrays (NSAs) composed of nanocrystals were fabricated via a facile galvanostatic electrodeposition technique. The as-prepared CoO NSAs exhibit excellent cyclability (retain 1000 mA h g−1 after 100 cycles at 1 A g−1) and rate capability (520 mA h g−1 at 10 A g−1) when they are directly used as an anode for LIBs.

Nitrogen-doped bamboo-like carbon nanotubes: promising anode materials for sodium-ion batteries

Nitrogen-doped bamboo-like carbon nanotubes (N-BCNTs) were synthesised using a facile one-step pyrolysis process. Due to their unique one-dimensional hollow structure and intrinsic high nitrogen content, N-BCNTs exhibit high capacity, superior rate capability, and excellent cycle stability and are, thus, promising anode materials for sodium-ion batteries.

Hierarchical Mesoporous/Macroporous Perovskite La0.5Sr0.5CoO3–x Nanotubes: A Bifunctional Catalyst with Enhanced Activity and Cycle Stability for Rechargeable Lithium Oxygen Batteries

Perovskites show excellent specific catalytic activity toward both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline solutions; however, small surface areas of the perovskites synthesized by traditional sol-gel methods lead to low utilization of catalytic sites, which gives rise to poor Li-O2 batteries performance and restricts their application. Herein, a hierarchical mesporous/macroporous perovskite La0.5Sr0.5CoO3-x (HPN-LSC) nanotube is developed to promote its application in Li-O2 batteries. The HPN-LSC nanotubes were synthesized via electrospinning technique followed by postannealing. The as-prepared HPN-LSC catalyst exhibits outstanding intrinsic ORR and OER catalytic activity. The HPN-LSC/KB electrode displays excellent performance toward both discharge and charge processes for Li-O2 batteries, which enhances the reversibility, the round-trip efficiency, and the capacity of resultant batteries. The synergy of high catalytic activity and hierarchical mesoporous/macroporous nanotubular structure results in the Li-O2 batteries with good rate capability and excellent cycle stability of sustaining 50 cycles at a current density of 0.1 mA cm(-2) with an upper-limit capacity of 500 mAh g(-1). The results will benefit for the future development of high-performance Li-O2 batteries using hierarchical mesoporous/macroporous nanostructured perovskite-type catalysts.

Porous Na3V2(PO4)3@C nanoparticles enwrapped in three-dimensional graphene for high performance sodium-ion batteries

Porous Na3V2(PO4)3@C nanocomposites enwrapped in a 3D graphene network were prepared using a simple freeze-drying-assisted thermal treatment method. The carbon layer and 3D graphene network provide not only a 3D conductive network but also a double restriction on the aggregation of Na3V2(PO4)3 particles that have a high crystallinity under high temperature treatment. Due to the high electrochemical activity of the highly crystalline Na3V2(PO4)3 nanoparticles and 3D conductive network, the novel NVP@C/G material displays a superior rate capability (76 mA h g−1 at 60C) and ultra-long cyclability (82% capacity retention for 1500 cycles at 40C) when used in sodium-ion batteries.

Nitrogen-doped porous carbon derived from residuary shaddock peel: a promising and sustainable anode for high energy density asymmetric supercapacitors

Exploring high-performance negative electrode materials is one of the great challenges in the development of high-energy density asymmetric supercapacitors (ASCs). Herein, a new kind of high-performance nitrogen-doped nanoporous carbon (NPC) electrode with a large surface area and abundant micropores/mesopores was derived from conveniently available fruit waste (shaddock peel) via a facile pyrolysis process. Electrochemical measurements showed that the as-synthesized NPC electrodes possessed a remarkably large capacitance of 321.7 F g−1 with good rate capability and excellent long-term cycling stability. Such excellent electrochemical performance was achieved by shortening the diffusion distance, increasing the electrode–electrolyte contact area and improving the electron conductivity of the NPC electrode arising from its nanoporous architecture and nitrogen doping. As a prototype, an all-solid-state ASC device based on the NPC negative electrode and a MnO2 positive electrode achieved an ultrahigh energy density of 82.1 W h kg−1 at a power density of 899 W kg−1, which is considerably larger than most reported carbon based supercapacitor devices.

Novel nitrogen-rich porous carbon spheres as a high-performance anode material for lithium-ion batteries

Carbonaceous materials with suitable structure and components are highly desirable for the development of lithium ion batteries (LIBs), since they can produce the best possible result by combining the advantages of the various structures and different components. To this end, herein, novel nitrogen-rich porous carbon spheres (N-PCS) with an appropriate pores distribution are proposed and prepared by using a template-assisted self-assembly method. The as-prepared N-PCS possess a high nitrogen content (>5%) and exhibit an interconnected sphere structure with large quantities of mesopores. As expected, the N-PCS display superior electrochemical performances, such as a high initial columbic efficiency (>60%), super cycle stability (retention of 540 mA h g−1 after 100 cycles at 0.5 A g−1), and good rate capability (215 mA h g−1 at 3 A g−1), thereby showing great promise as anode materials for the next generation of LIBs.

A high strength, free-standing cathode constructed by regulating graphitization and the pore structure in nitrogen-doped carbon nanofibers for flexible lithium–sulfur batteries

We demonstrate here a novel strategy to prepare a flexible and free-standing sulfur cathode with improved mechanical strength, the matrix of which is constructed from graphitized nitrogen-doped mesoporous carbon nanofibers (NPCFs). Benefiting from a unique micro/mesoporous structure and highly graphitic carbon, the NPCF film is capable of accommodating more sulfur, and maintains substantially higher mechanical strength and flexibility after sulfur loading as compared with traditional microporous carbon nanofiber films. As a free-standing and flexible cathode for Li–S batteries, the robust composite film exhibits excellent rate capability (540 mA h g−1 at 5C) and cycling stability (76.5% retention after 500 cycles at 5C).