The heteroatom doping strategies have been utilized to effectively improve the performance of the carbon-based hosts, such as graphene, for lithium (Li) metal in high energy density lithium metal batteries. However, solely doped graphene hosts often need the assistance of other materials with either better lithiophilicity or electronic conductance to achieve smooth and efficient deposition of Li, which adds extra weight or volume. Herein, graphene co-doped by nitrogen and fluorine (NFG) is employed as a stable host for Li, where the N-doping provides lithiophilicity and electronic conductivity lacked by F-doping and the F-doping facilitate fast formation of solid electrolyte interphase (SEI) retarded by N-doping. The well regulation of Li plating/stripping and SEI formation is verified by quickly stabilized and small-magnitude voltage hysteresis, which stands out in Li hosts based on doped graphene and leads to excellent long-term cycling performance of NFG based electrodes. A voltage hysteresis of 20 mV is observed for more than 850 h in the symmetrical cell. The remarkable efficiency of lithium usage is confirmed by the high-capacity retention of a full cell paired with LFP, which exceeds 70% after 500 cycles. This work presents an innovative perspective on the control of Li plating/stripping by simultaneously introducing two kinds of dopants into graphene and paving the way for exploring practical Li metal batteries.

Sodium (Na) metal batteries (SMBs) have emerged as promising alternatives to lithium metal batteries for large-scale energy storage applications, owing to their cost-effectiveness, abundance, and favorable redox potential. However, the practical implementation of SMBs faces several challenges associated with the Na metal anode, including the formation of dendrites, low Coulombic efficiency, and capacity fading. Here, we propose a novel approach to enhance the electrochemical performance of Na metal anodes through a porous Al-Cu alloy host (PAC) fabricated by a local eutectic melting engineering. The local eutectic melting facilitates the development of a conductive network, offering mechanical support, and the porous structure provides abundant channels for the diffusion of Na ions and accommodates volume fluctuations in the Na metal during charge–discharge cycling. Moreover, the PAC exhibits a high average Coulombic efficiency of 99.8% at 1 mA·cm⁻² for 1 mAh·cm⁻² and a low voltage polarization of 19 mV during 500 cycles. This study provides valuable insight into the design and fabrication of high-performance Na metal anodes, which hold significant promise for the advancements of next-generation energy storage systems.

Vanadium oxides have attracted extensive interest as electrode materials for many electrochemical energy storage devices owing to the features of abundant reserves, low cost, and variable valence. Based on the in-depth understanding of the energy storage mechanisms and reasonable design strategies, the performances of vanadium oxides as electrodes for batteries have been significantly optimized. Compared to crystalline vanadium oxides, amorphous vanadium oxides (AVOs) show many unique properties, including large specific surface area, excellent electrochemical stability, lots of defects and active sites, fast ion kinetics, and high elasticity. This review gives a comprehensive overview of the recent progress on AVOs for different energy storage systems, such as alkali metal ion batteries, multivalent ion batteries, and supercapacitors with a special focus on the preparation strategies. The basic mechanisms for energy storage performance improvements of AVOs as compared to their crystalline counterparts are also introduced. Finally, challenges faced by AVOs are discussed and future development prospects are also proposed. This review aims to provide a comprehensive knowledge of AVOs and is expected to promote the development of high-performance electrodes for batteries.

We reported the growth of horizontally aligned nitrogen-doped single-walled carbon nanotubes (SWNTs) on quartz substrates. The synthesized SWNTs were comprehensively characterized at the single nanotube level. Owing to the highly aligned nature of the nanotubes, we were able to investigate the diameter dependent doping mechanism through systematic resonant Raman spectroscopy studies. Other than the formerly found narrowing effect by N-doping, we proposed that the nanotube diameter affects the introduction of N atoms into the carbon lattice in an elaborate way. The obtained doping level increased along with the nanotube diameter but lost the increasing trend when the diameter became larger and experienced a slight decrease after reaching the local peak value. These insights about the heteroatom doping into the carbon nanotubes could benefit the development of the carbon nanotube based functional materials and extend their application in a broad range of areas.

The easy oxidation and surface roughness of Cu nanowire (NW) films are the main bottlenecks for their usage in transparent conductive electrodes (TCEs). Herein, we have developed a facile and scaled-up solution route to prepare Cu NW-based TCEs by embedding Cu NWs into pre-coated smooth poly(3, 4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT: PSS) films on poly(ethylene terephthalate) (PET) substrates. The so obtained Cu NW-PEDOT: PSS/PET films have low surface roughness (~70 nm in height), high stability toward oxidation and good flexibility. The optimal TCEs show a typical sheet resistance of 15 Ω·sq^-1 at high transparency (76% at λ = 550 nm) and have been used successfully to make polymer (poly(3-hexylthiophene): phenyl-C61-butyric acid methyl ester) solar cells, giving an efficiency of 1.4%. The overall properties of Cu NW-PEDOT: PSS/PET films demonstrate their potential application as a replacement for indium tin oxide in flexible solar cells.