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Lithium-ion batteries (LIBs) are rechargeable batteries that have attracted great interest as next-generation energy storage devices that will lead future energy technologies because of their various excellent advantages. Two-dimensional (2D) MXene-based LIBs have been actively investigated because of their high energy/power density and good performance at high charge/discharge rates. However, three major limitations of 2D MXene electrodes -self-stacking, low specific surface area, and disturbance of Li + diffusion by surface terminations -have hindered the commercialization of MXene-based LIBs. Herein, we fabricate 1D hollow Ti 3 C 2 T x MXene/carbon (MX/C) nanofibers via an electrospinning process and use them as anode materials in LIBs. Compared with the pristine 2D MXene (MX) paste electrode and MXene/carbon (MX/C) paste electrode, the hollow MX/C nanofibers electrode exhibits a greater specific surface area, less self-stacking of flakes, and surface functional groups tailored for LIBs. The LIBs based on the hollow electrode exhibit a higher energy density (306.5 mA h g À 1 at 40 mA g À 1 ) than those with the MX paste electrode (81.08 mA h g À 1 at 40 mA g À 1 ) and MX/C paste electrode (196.9 mA h g À 1 at 40 mA g À 1 ). In addition, the hollow MX/C nanofiber electrode shows a high reversible capacity, proving that it is a promising anode material for LIBs.

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Alkali-activated ground granulated blast-slag (AAS) is the most obvious alternative material for ordinary Portland cement (OPC). However, to use it as a structural material requires the assessment and verification of its durability. The most important factor for a durability evaluation is the degree of carbonation resistance, and AAS is known to show lower performance than OPC. A series of experiments was conducted with a view to investigate the carbonation characteristics of AAS binder. As a consequence, it was found that the major hydration product of AAS was calcium silicate hydrate (CSH), with almost no portlandite, unlike the products of OPC. After carbonation, the CSH of AAS turned into amorphous silica gel which was most likely why the compressive strength of AAS became weaker after carbonation. An increase of the activator dosage leads AAS to react more quickly and produce more CSH, increasing the compaction, compressive strength, and carbonation resistance of the microstructure.

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