Effect of Tungsten and Carbon in Germanium Oxide as a High-Performance Electrode for Energy Storage Applications

The worldwide acceptance of electric vehicles requires higher capacity anode materials for achieving better energy density. For that, researchers have been investigating silicon-based composite anode materials to mitigate the intrinsic volume expansion during electrochemical cycling. Unfortunately, the volume expansion of silicon led to poor cyclability and practical viability. This work concentrated on GeO2-based composites that show comparably low intrinsic volume expansion than silicon. Hence, we studied two composites: (i) GeO2@W (binary composite) and (ii) GeO2@W@C (ternary composite) for application in Li-ion and Na-ion batteries (LIBs and SIBs) and supercapacitors (SCs). Appropriate tools were adopted to confirm the structural, elemental, morphological, and textural properties of the as-mentioned two different composites. When the cell is cycled at a low current density of 100 mA g(-1), the LIBs of binary and ternary composites deliver appreciable discharge capacities of 1214 and 1387 mAh g(-1) with initial Coulombic efficiencies (ICEs) of 71.3 and 76.4%, whereas the SIBs deliver discharge capacities of 201 and 365 mAh g(-1) with ICEs of 55.1 and 78.5%, respectively. For supercapacitors, the ternary composite exhibits a specific capacitance of 277 F g(-1) at a current rate of 10 A g(-1). The superior electrochemical performances of the ternary composite attract wide attention in both high energy and high power density applications.