Exploring tin oxide based materials: A critical review on synthesis, characterizations and supercapacitive energy storage

[Display omitted] •State-of-art for synthesis of tin oxide-based materials towards supercapacitor applications.•Widespread synthetic routes bare SnO2, SnO2 with composite, metal doped, metal doped composites.•Supercapacitors through single electrode, liquid, solid-state, symmetric, asymmetric modes.•Demonstrating of supercapacitor from small scale to advance wearable applications.•Present challenges with future prospects for SnO2 based materials for supercapacitor. Increased population causing need of efficient energy storage devices possessing high energy density and environmental friendliness. Electrochemical supercapacitor is one who can fulfil the future demands. In this regard, many materials have been synthesized towards low-cost fabrication process to serve as efficient and effective energy storage supercapacitive devices but not up to the mark in wide-spread applications and commercially large-scale production. Tin oxide is cheap, earth abundant, electrically conductive, and a structurally stable material and poses pseudocapacitive behavior. In this regard, present review explores tin oxide-based materials towards active electrode material for supercapacitor applications. Supercapacitors can be classified as electrochemical double layer (EDLC) behaved where charge store at electrode-electrolyte interface possessing high stability but suffers through low capacitance. Contrary, pseudocapacitive through redox reactions possess high capacitance but suffers through low stability. High stability with high capacitance can be achieved through ‘material mutualism’ between EDLC and pseudocapacitive behaved materials, where tin oxide behaves as a pseudocapacitive material. Hence, critical review explores not only bare tin oxide material but also its composites with carbon-based materials, polymers, metal oxides, metal sulfides, ternary nanocomposites, and it’s doping along with composite formation as well. These are well categorised through wide spread synthetic routes such as hydrothermal, chemical precipitations, electrochemical deposition, spray pyrolysis, chemical bath deposition, successive ionic layer adsorption and reaction, electrospinning, sonochemical, atmospheric pressure plasma jet and thermal evaporation from synthesis, characterization to application part. Supercapacitors through single electrode, liquid and solid-state configured symmetric and asymmetric devices have been well explored along with highlights for the future scope inclusive of fle