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Solution-printable and flexible thermoelectric materials have attracted great attention because of their scalable processability and great potential for powering flexible electronics, but it is challenging to integrate mechanical flexibility, solution-printability and outstanding thermoelectric properties together. In particular, such an n-type thermoelectric material is highly sought after. In this paper, 2D TiS 2 nanosheets were exfoliated from layered polycrystalline powders, and then assembled with C 60 nanoparticles, resulting in a new class of flexible n-type thermoelectric materials via a concurrent enhancement in the power factor and a reduction in thermal conductivity. The resultant C 60 /TiS 2 hybrid films show a ZT ∼ 0.3 at 400 K, far superior to the state-of-the-art solution-printable and flexible n-type thermoelectric materials. In particular, such a thermoelectric property rivals that of single-crystal TiS 2 -based thermoelectric materials, which are expensive, difficult to synthesize, and unsuitable for solution printing. A solution of the C 60 /TiS 2 hybrid was also used as an ink for printing large-area flexible and spatial thermoelectric devices. An outstanding output power of 1.68 W m −2 was generated at a temperature gradient of 20 K. This work paves the way for flexible, solution-printable, high-performance thermoelectric materials for flexible electronics. 

Switching from organic to aqueous solvents for battery electrode processing is desirable due to both safety and cost advantages. Lithium iron phosphate (LFP) is considered a cathode material for aqueous processing due to its demonstrated chemical compatibility with water, in addition to its favorable cost, safety, electrochemical performance, and environmental advantages as a battery active material. All research on LFP stability in water has been conducted in a scenario where LFP is aged in stagnant water, or surrounded by water when confined within a composite electrode. However, a much accelerated degradation in the electrochemical performance of LFP when it is in contact with water and exposed to mechanical agitation is demonstrated. Changes to LFP are probed using a combination of materials characterization methods. Although there are no significant changes to the bulk particle structure and morphology, significant particle surface damage and compositional modifications are observed. These results suggest that the systems where LFP is exposed to agitation in an aqueous environment, such as in aqueous battery electrode processing or in aqueous slurry electrodes, need to be carefully investigated for potential changes to the LFP surface environment under relevant processing conditions.