Electrolytes in batteries must cater to the needs of both electrode chemistries because of their omnipresence and essence in our daily life. Over the past few decades, a significant advancement in battery electrode materials has been perceived as compared to the conventional electrolyte systems consisting of metal salts and organic carbonate solvents. With the ever-increasing technological advancement and consumer demand for battery performance, it is a demanding part of the job to improve the electrochemical dynamics and electrolytic interactions with its electrode interfacial chemistries. To sustain the current desired technological trajectory, it is obvious to study and explore unconventional electrolyte systems, including solvent-in-salt systems and solid-state electrolyte systems. Very few studies have reported on novel electrolyte systems and their state-of-the-art analysis. This chapter inherits the previous studies and comprehensively examines the recent advances in novel electrolytic systems in rechargeable batteries with insightful comments for readership benefits.