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Abstract Herein we report the successful use of a polyisoindigo derivative (P(iso)) as a new conductive binder inside electrode formulations containing silicon nanoparticles covered with a carbon shell (Si@C) for Li-ion batteries. The expected role of the carbon shell is to stabilize the Solid Electrolyte Interphase layer (SEI) to prevent it from cracking under nanoparticle volume variations during lithiation processes. The P(iso) conducting polymer is used to act both as mechanical binder and n-type conductive component in replacement of usual carbonaceous additive materials. Ultimately, the cumulative contributions of both materials inside a two-electrode component formulation (Si@C P(iso)) aim to address the stability drawbacks commonly faced by silicon electrodes. Physico-chemical characterizations revealed that the Si@C nanoparticles are uniformly embedded inside the polymeric matrix. Electrochemical measurements in half-cells clearly show the formation of Li Si alloys during cycling. Moreover specific capacities up to 1400 mAh/g with a remarkable stability until 500 cycles have been achieved, proving this conductive polymer to be a valid alternative to classical polymeric binders mixed with carbonaceous additives. These very promising results highlight the use of this polyisoindigo family as new conductive binders inside Si@C electrode formulations for Li-ion battery applications. Highlights • Synthesis of a polyisoindigo derivative (P(iso)) by Yamamoto cross-coupling. • Characterization of the (P(iso)) as a new conductive binder with Si@C nanoparticles. • High stability of the Si@C P(iso) electrode (1400 mAh/g) over 500 cycles. • Higher capacity retention for Si@C P(iso) electrode than Si@C/CMC/CB electrode. [ABSTRACT FROM AUTHOR]

Graphene hydrogels with high electrical conductivity were prepared by a one-step process using hydrazine hydrate as gel assembly agent (GH-HD). Conventional two-step process of gel formation and further reduction to prepare highly conducting gels was replaced by a single step involving equivalent amount of hydrazine. Optimized graphene oxide concentration was established to facilitate such monolith formation. Extensive characterization and control studies enabled understanding of the material properties and gel formation mechanism. The synthesized gel shows a high electrical conductivity of 1141 S/m. The supercapacitor based on GH-HD delivers a high specific capacitance of 190 F/g at a current density of 0.5 A/g and 123 F/g at very high current density of 100 A/g. Furthermore, excellent power capability and cyclic stability were also observed. 3D macroporous morphology of GH-HD makes it ideal for high rate supercapacitor applications. [ABSTRACT FROM AUTHOR]