Strengthening mechanisms, deformation behavior, and anisotropic mechanical properties of Al-Li alloys: A review

Potassium-ion batteries (PIBs) have been regarded as promising alternatives to lithium-ion batteries in large-scale energy storage systems owing to the high abundance and low cost of potassium. However, the large radius of the K-ion hinders the development of suitable electrode materials. In this work, we confine SnS2 in N,S co-doped carbon nanofibers as anode materials for PIBs with high reversible capacity (457.4 mA h g−1@0.05 A g−1), remarkable cycling stability (1000 cycles@2.0 A g−1), and superior rate capability (219.4 mA h g−1@5.0 A g−1), overmatching most of the reported studies. The origin of the high reversible capacity is revealed by in situ XRD techniques. The combined capacitive and diffusion-controlled behaviors are disentangled through consecutive CV measurements. Combining the Randles–Sevcik equation and dQ/dV plots, correlations between the K-ion storage behaviors and diffusion kinetics at various potassiation depths are constructed. Theoretical calculations on K adsorption affinities at various N,S co-doped sites illuminate the synergistic effects of the N,S co-doping strategy in boosting the K-ion transport kinetics. Moreover, foldable potassium-ion full cells are successfully assembled with stable cycling performance, showing application potential in flexible electronic devices. These findings will boost the rational design and mechanistic understanding of anode materials in PIBs and related energy storage devices.

Foldable potassium-ion batteries enabled by free-standing and flexible SnS2@C nanofibers

The effects of aging treatments on mechanical property and corrosion behavior of spray formed 7055 aluminium alloy

Corrosion behaviour of 2A97-T6 Al-Cu-Li alloy: The influence of non-uniform precipitation

The development of high-performance potassium ion battery (KIB) electrodes requires a nanoengineering design aimed at optimizing the construction of active material/buffer material nanocomposites. These nanocomposites will alleviate the stress resulting from large volume changes induced by K+ ion insertion/extraction and enhance the electrical and ion conductivity. We report the synthesis of phosphorus-embedded ultrasmall bismuth-antimony nanocrystals (BixSb1-x@P, (0 ≤ x ≤ 1)) for KIB anodes via a facile solution precipitation at room temperature. BixSb1-x@P nanocomposites can enhance potassiation-depotassiation reactions with K+ ions, owing to several attributes. First, by adjusting the feed ratios of the Bi/Sb reactants, the composition of BixSb1-x nanocrystals can be systematically tuned for the best KIB anode performance. Second, extremely small (diameter ≈ 3 nm) BixSb1-x nanocrystals were obtained after cycling and were fixed firmly inside the P matrix. These nanocrystals were effective in buffering the large volume change and preventing the collapse of the electrode. Third, the P matrix served as a good medium for both electron and K+ ion transport to enable rapid charge and discharge processes. Fourth, thin and stable solid electrolyte interface (SEI) layers that formed on the surface of the cycled BixSb1-x@P electrodes resulted in low resistance of the overall battery electrode. Lastly, in situ X-ray diffraction analysis of K+ ion insertion/extraction into/from the BixSb1-x@P electrodes revealed that the potassium storage mechanism involves a simple, direct, and reversible reaction pathway: (Bi, Sb) ↔ K(Bi, Sb) ↔ K3(Bi, Sb). Therefore, electrodes with the optimized composition, i.e., Bi0.5Sb0.5@P, exhibited excellent electrochemical performance (in terms of specific capacity, rate capacities, and cycling stability) as KIB anodes. Bi0.5Sb0.5@P anodes retained specific capacities of 295.4 mA h g-1 at 500 mA g-1 and 339.1 mA h g-1 at 1 A g-1 after 800 and 550 cycles, respectively. Furthermore, a capacity of 258.5 mA h g-1 even at 6.5 A g-1 revealed the outstanding rate capability of the Sb-based KIB anodes. Proof-of-concept KIBs utilizing Bi0.5Sb0.5@P as an anode and PTCDA (perylenetetracarboxylic dianhydride) as a cathode were used to demonstrate the applicability of Bi0.5Sb0.5@P electrodes to full cells. This study shows that BixSb1-x@P nanocomposites are promising carbon-free anode materials for KIB anodes and are readily compatible with the commercial slurry-coating process applied in the battery manufacturing industry.

Bi-Sb Nanocrystals Embedded in Phosphorus as High-Performance Potassium Ion Battery Electrodes

Antimony-based materials with high theoretical capacity are known as promising anodes for potassium-ion batteries (PIBs). However, they still face challenges from the large ionic radius of the K ion, which has sluggish kinetics. Much effort is needed to exploit high-performance electrode materials to satisfy the reversible capacity of PIBs. In this paper, nano Sb confined in N-doped carbon fibers (Sb@CN nanofibers) were successfully prepared through an electrospinning method, which was designed to improve potassium storage performances. Sb@CN nanofibers benefit from the fact that the synergy between the porous nanofiber frame structure and the uniformly distributed Sb nano-components in the carbon matrix can effectively accelerate the ion migration rate and reduce the mechanical stress caused by K+ insertion/extraction, Sb@CN nanofiber electrodes thus exhibited excellent potassium storage performance, especially long cycle stability, as expected. When utilized as a PIB anode, they delivered high reversible capacity of 360.2 mAh g−1 after 200 cycles at 50 mA g−1, and a particularly stable capacity of 212.7 mAh g−1 was also obtained after 1000 cycles even at 5000 mA g−1. Given such outstanding electrochemical performances, this work is expected to provide insight into the development and exploration of advanced alloy-type electrodes for PIBs.

Ultra-stable Sb confined into N-doped carbon fibers anodes for high-performance potassium-ion batteries

Intergranular corrosion of Zn-free and Zn-microalloyed Al–xCu–yLi alloys

Correlation of intergranular corrosion behaviour with microstructure in Al-Cu-Li alloy

The influence of pre-deformation on aging precipitates of three near peak-aged Al–Cu–Li alloys, 1460 alloy with a low Cu/Li ratio (1.46), 2050 alloy with a high Cu/Li ratio (4.51) and 2A96 alloy with a medium Cu/Li ratio (2.97), was investigated. The strength of the aged alloys is enhanced by the pre-deformation. The effectiveness of pre-deformation on precipitates is dependent on the alloy’s composition. With increasing the pre-deformation, the population density of T1 (Al2CuLi) precipitates increases in all three Al–Cu–Li alloys and their diameter decreases in 2050 and 2A96 alloys, and the greatest effectiveness is observed in 2A96 alloy. The pre-deformation also increases the population density of θ′ (Al2Cu) precipitates and decreases their diameter in 2050 and 2A96 Al–Li alloys, but the effectiveness is smaller compared to that on T1 precipitates. In 1460 alloy subjected to two-step aging at 130 °C for 20 h followed by 160 °C for 12 h, the main precipitates are δ′ (Al3Li). At 2%–6% pre-deformation, GP-I zones form and pre-deformation displays little influence. Eight percentage pre-deformation promotes θ″/θ′ precipitation and increases their population density.

Dan-yang Liu

Papers

Ultra-stable Sb confined into N-doped carbon fibers anodes for high-performance potassium-ion batteries

Intergranular corrosion of Zn-free and Zn-microalloyed Al–xCu–yLi alloys

Correlation of intergranular corrosion behaviour with microstructure in Al-Cu-Li alloy

Influence of Pre-deformation on Aging Precipitation Behavior of Three Al–Cu–Li Alloys

Distribution and evolution of aging precipitates in Al-Cu-Li alloy with high Li concentration