A Novel Rapid Processing Route to Sintered Plaque Aqueous Nickel Electrodes for Low Cost Building Scale Energy Storage

Abstract

Electrification of heating systems and transportation as well as decarbonisation of electrical energy production will continue to place more and more stress and strain on current electrical grid infrastructures. Renewable energy generation technologies such as photovoltaics and wind power generation are seen by many as the future for energy production and security. With high dependence on such intermittent and ‘highly distributed micro-generation’ energy production technologies, ‘highly distributed micro-storage’ solutions such as secondary batteries could prove to be the answer. An appropriate technology would ideally possess a lifetime in-line with current photovoltaic technologies (20 years), be inherently safe and be able to cope with the unpredictable cycling conditions posed by intermittent generation and user demand. One such technology, namely nickel-iron aqueous batteries (pioneered by Thomas Alva Edison in 1901) boasts cycle life in excess of 5000 cycles, as well as tolerance of both physical and electrical abuse. Low energy density (both gravimetrically and volumetrically) are long standing issues with the chemistry, however given the nature of the application, such issues are not of the greatest concern. The greatest issue posed by the nickel cathode material is the poor high rate charge/discharge capability, due to the insulating nature of nickel hydroxide active materials. This can be addressed by configuring the cathode active material within a conductive scaffold (sintered nickel plaque on nickel-plated steel current collector). This does however hinder manufacturability of the cathode, requiring a highly energy intensive heat treatment (900oC, 30 minutes). Herein we evaluate electrodes produced via 2 process routes: - A traditional process route consisting of a slurry deposition and subsequent convection sintering process and a continuous current active material deposition process, versus a novel rapid process route, utilising high volume throughput screen printing of both nickel and titanium dioxide scaffolds and Near Infrared rapid curing technology, as well as a pulsed current active material deposition. The latter results in a substantial reduction in manufacture time, opening the door to semi-continuous processing for sintered nickel battery technologies and therefore low-cost energy storage.