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The uneven formation of a solid-electrolyte interphase (SEI) in Li-ion batteries (LIBs) results in continuous electrolyte consumption and poor ionic conductivity, leading to degradation of the electrochemical performance. In this study, we report the optimal conditions for SEI formation to achieve enhanced electrochemical performance of a SiO x anode in LIBs using a pre-lithiation under short-circuitcontaining constant-resistance (PLSC) process. The SiO x electrode prepared using the PLSC process delivers more outstanding cycle life (capacity retention of ∼88.6% over 500 cycles) than that of an electrode prepared using the normal discharging process. Furthermore, PLSC process results in significantly improved power capability of SiO x with a capacity retention of ∼66.6% at 3 A g −1 (vs. the capacity measured at 0.1 A g −1 ).

The surface morphologies of the active electrode materials have a significant impact on the electrochemical performance of supercapacitors. The Ni-mixed CuCo2S4 materials were successfully prepared on Ni-Foam using the hydrothermal method followed by the sulfidation process. CuCo1.5Ni0.5S4 has a nanoneedle structure, whereas CuCo1.0Ni1.0S4 has a vertically aligned nanograss structure. Due to the high theoretical capacity and redox behavior of Ni, Co, and Cu elements, the low electronegativity of S atoms, favorable structural behavior, and low hydration sphere radius with high ionic mobility character of OH– ions, the resulting CuCo1.0Ni1.0S4 nanograss was used as a binder-free electrode for supercapacitor application. It has delivered outstanding specific capacity, rate capability, and cycle performance characteristics. The CuCo1.0Ni1.0S4 electrode produced a maximum specific capacity of 325.5 mA h/g at a current density of 1 A/g, while maintaining good rate capability. After 5000 cycles at 20 A/g, the CuCo1.0Ni1.0S4 electrode retains 86% of its initial capacity. Furthermore, the asymmetric supercapacitor device is made with CuCo1.0Ni1.0S4 as the positive electrode material and activated carbon as the negative electrode material. The fabricated ASC has a maximum energy density of 38.5 W h/kg at a power density of 356 W/kg. In summary, the CuCo1.0Ni1.0S4 electrode is a promising material for electrochemical energy storage and conversion applications.

A Si-based anode maintaining its high electrochemical performance with cycles was prepared for the nondegradable lithium-ion battery. Nanoscaled Si particles were mechanochemically coupled with approximately 3 nm thick oxide layer and n-carbon (nanoscaled carbon) crystallites to overcome silicon’s inherent problems of poor electronic conductivity and severe volume change during lithiation and delithiation cycling. The oxide layer of SiO x was chemically formed via a controlled oxygen environment during the process; meanwhile, the n-carbon crystallites were obtained by mechanical fragmentation from ∼70 μm sized multilayered graphene powders with a low degree of agglomeration. The Si-based composite anode, processed by the above-mentioned mechanochemical coupling, maintained a superior discharge capacity of 1767 mA h/g through 100 cycles with a Coulombic efficiency exceeding 98% at a current density of 100 mA/g. According to our current study, the coupling of the Si particles with oxide layer and n-carbon crystallites was found to be a significantly efficient way to prevent the performance degradation of the Si-based anode.