An advanced Ni–Graphite molten salt battery with 95 °C operating temperature for energy storage application

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2022-05, Vol.435, p.135110, Article 135110
• Main Authors: Zhang, Wenlong, Liao, Chenzheng, Ning, Xiaohui
• Format: Article
• Language: English
• Subjects: Low operating temperature; Molten salt battery; Ni-graphite battery
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2022.135110

•A Ni-Graphite battery presented based on quaternary molten salts electrolyte.•Average voltage of 1.7 V and working at 95 °C enabled in Ni-Graphite battery.•Coulombic efficiency improved by pre-compensating Ni powder and amorphous carbon.•Ni-Graphite battery shows capacity of 174 mAh/g and energy density of 289 Wh/kg. Based on the high safety and low costs, molten salt batteries (Na-S battery, liquid metal battery, ZEBRA battery, etc.) have received more and more attention as large-scale electrical storage technology. However, the high operating temperature of molten salt batteries is still one of the roadblocks that impeded their practical application. Here we present the novel Ni-graphite molten salt battery based on outstanding electrochemical reversibility of the Ni/NiCl2 redox and intercalation/de-intercalation chemistry of chloroaluminate anions in graphite. By using the low-cost, quaternary inorganic molten salt AlCl3/KCl/NaCl/LiCl as electrolyte, the as-designed Ni-graphite battery possesses low operating temperature of 95 °C, and average voltage about 1.7 V. The Ni-graphite battery delivers stable specific capacity of 174 mAh/g at 500 mA/g after 120 cycles, with the capacity retention rate of 98%. In addition, the Ni-graphite battery also shows low material costs about 113.6 $/kWh and high electrode energy density of 289 Wh/kg. This work develops an advanced molten salt battery with low operating temperature and high energy density, as well as provides an alternative means of developing future large-scale power storage equipment based on molten salt batteries.