A study was conducted on the Felder-Soloman Index of Learning Styles © (ILS) to assess reliability, factor structure, and construct validity as well to determine whether changing its dichotomous response scale to a five-option response scale would improve reliability and validity. Data collected in this study had internal consistency reliability ranging from 0.55 to 0.77 across the four learning style scales of the ILS. Factor analysis revealed that multiple factors were present within three of the learning style scales, which correspond to known aspects of the scale definitions. The factor analysis and direct feedback from students on whether they felt their scores accurately represented their learning preferences provide evidence of construct validity for the ILS. Changing the response scale improved reliability, but it did not change the factor structure substantially nor did it affect the strength of the evidence for construct validity based on student feedback.

We investigate the use of chitosan (CS) as a new cross-linkable and water-soluble binder for the Si anode of Li-ion batteries. In contrast to the traditional binder utilizing a hydrogen bond and/or van der Waals force-linked anode electrodes, CS can easily form a 3D network to limit the movement of Si particles through the cross-linking between the amino groups of CS and the dialdehyde of glutaraldehyde (GA). Chemical, mechanical, and morphological analyses are conducted by Fourier transform infrared spectroscopy, tensile testing, and scanning electron microscopy. The cross-linked Si/CS-GA anode exhibits an initial discharge capacity of 2782 mAh g(-1) with a high initial Coulombic efficiency of 89% and maintained a capacity of 1969 mAh g(-1) at the current density of 500 mA g(-1) over 100 cycles.

Polymeric binder is extremely important for Si-based anode in lithium-ion batteries due to large volume variation during charging/discharging process. Here, natural rubber-incorporated chitosan networks were designed as a binder material to obtain both adhesion and elasticity. Chitosan could strongly anchor Si particles through hydrogen bonding, while the natural rubber could stretch reversibly during the volume variation of Si particles, resulting in high cyclic performance. The prepared electrode exhibited the specific capacities of 1350 mAh/g after 1600 cycles at the current density of 8 A/g and 2310 mAh/g after 500 cycles at the current density of 1 A/g. Furthermore, the cycle test with limiting lithiation capacity was conducted to study the optimal binder properties at varying degree of the volume expansion of silicon, and it was found that the elastic property of binder material was strongly required when the large volume expansion of Si occurred.

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