Two birds with one stone: Bimetallic ZnCo2S4 polyhedral nanoparticles decorated porous N-doped carbon nanofiber membranes for free-standing flexible anodes and microwave absorption

Cost-efficient material with an ingenious design is important in the engineering applications of flexible energy storage and electromagnetic (EM) protection. In this study, bimetallic ZnCo2S4 (ZCS) polyhedral nanoparticles homogenously embedded in the surface of porous N-doped carbon nanofiber membranes (ZCS@PCNFM) have been fabricated by electrospinning technique combined with carbonization and hydrothermal processes. As a self-assembled electrode for lithium-ion batteries (LIBs), the bimetallic ZCS nanoparticles possess rich redox reactions, good electrical conductivity, and pseudocapacitive properties, while the three-dimensional (3D) multiaperture architecture of the nanofiber film not only shortens the transfer spacing of lithium ions and electrons but also effectively tolerates the volume variation during lithiation and delithiation cycles. Benefiting from the above merits, the ZCS@PCNFM electrode exhibits good cycle performance (662.3 mA h/g at 100 mA/g after 100 cycles), superior rate capacity (401.3 mA h/g at 1 A/g) and an extremely high initial specific capacity of 1152.2 mAh/g at 100 mA/g. Meanwhile, depending on the hierarchical nanostructure and multi-component heterogeneous interface effects constructed by 3D inlaid architecture, the ZCS@PCNFM nanocomposite exhibits fascinating microwave absorption (MA) characteristics with a superhigh reflection loss (RL) of -49.7 dB at a filling content of only 20 wt% and corresponding effective absorption bandwidth (EAB, RL<-10 dB) of 5.2 GHz ranging from 12.8 to 18.0 GHz at 2.2 mm.

Se/N co-doped carbon nanorods for potassium ion storage

Herein, we make use of the large-sized Se atom to regulate the local structure of the graphitic lattice to optimize N-doping species to strengthen the adsorption of K+, which can greatly boost the capacitive capacity for PIBs.

A new strategy for achieving high K+ storage capacity with fast kinetics: realizing covalent sulfur-rich carbon by phosphorous doping

Designing carbon anodes with rich heteroatoms and dilated graphitic interlayer spacing via a one-step synthesis process plays a vital role in accelerating the practical application of potassium ion batteries, but it is still a big challenge. Herein, P-doped S-rich mesoporous carbon (PSMC) is prepared by direct phosphate-assisted carbonization of carrageenan, and it exhibits excellent potassium storage capacity (449 mA h g-1 at 0.1 A g-1), superior rate performance (233 mA h g-1 at 2 A g-1) and long-term stability (97.3% capacity retention after 1000 cycles), due to the high sulfur doping (16.48 wt%) and the coexistence of ordered and disordered regions in the structure. Ex situ characterization, GITT and theoretical calculations reveal that the promotion of covalent sulfur can effectively increase the adsorption of K+ and enhance the K+ reaction kinetics. The proposed one-step synthesis strategy demonstrates the precise use of the composition in biomass, enabling large-scale production of high-performance anodes for K+ storage.