Heat charging towards electrical energy saving and high-efficiency Zn-ion batteries

The energy efficiency of batteries is generally compromised by internal resistance and polarization, which lead to considerable energy losses in widespread applications. Herein, we save the electrical energy and enhance energy efficiency by simultaneously charging Zn-ion batteries using waste heat and electricity. Using first-principles calculations and the modified Nernst equation, a high entropy Layered Double Hydroxide (LDH) reaction was introduced into the anode of a NiHCF/Zn battery, leading to a record absolute temperature coefficient of 3.157 mV K−1 and a massive heat absorption during the charging process. Then the modified battery was charged at 45 °C and normally discharged at 5 °C, significantly saving 11.23% of electrical energy during charging and elevating the energy efficiency to 105.16%. Additionally, the NiHCF/Zn-LDH battery exhibits extraordinary stability, enduring over 1000 charge/discharge cycles with a capacity fade of less than 4.27%. This work demonstrates that large energy saving and surpassing 100% energy efficiency through heat charging are feasible, presenting a potential technology for enhancing energy conservation in battery applications.