Towards the development of a novel bipolar-based battery in aqueous electrolyte: Evaluation of the electrochemical properties of NiCu based hydroxide electrodes fabricated on Ni–mesh and graphite composite current collectors

Abstract

The use of bipolar electrodes in rechargeable batteries can improve specific power, simplify cell design, and reduce manufacturing costs. However, bipolar-based batteries still suffer from many drawbacks. Therefore, developing high-performance active materials and developing improvement strategies encompassing the entire cell's design is essential. The current collector significantly impacts the viability of mass production; however, it is the most neglected feature of electrochemical energy storage devices. The current collector serves a dual purpose; it allows the movement of electrons among active electrode material and provides mechanical support. It can also act as transportation of current to terminals of the battery. This study constructed a novel bipolar battery cell utilizing graphite as a current collector, and its discharge capacities for Ni-Fe battery applications were evaluated. Monopolar NiFe cells, one using a graphite substrate current collector and the other using a Ni-mesh current collector, were used for comparison. The monopolar-based electrode coated onto a graphite substrate demonstrated a 29% (199 mAh/g) higher discharge capacity than the Ni-mesh-based electrode (142 mAh/g) after the 100th cycle. In contrast, the bipolar-based NiFe battery cell resulted in a discharge capacity of 158 mAh/g after the 100th cycle, corresponding to a coulombic efficiency of 72%.