Single-Shell Multiple-Core MnO@C Hollow Carbon Nanospheres for Low-Temperature Lithium Storage

Abstract

Lithium-ion batteries (LIBs) have been extensively employed in a range of electrical vehicles and portable devices in virtue of their high energy density and stable cycle life. However, poor performance under low temperatures hinders their application in cold climates and regions. Herein, single-shell (carbon) multiple-core (ultra-small MnO@C nanoparticles) hollow carbon nanospheres (MnO@C@HCS) were prepared by a sacrificial template method, and MnO@C@HCS showed excellent low-temperature electrochemical performance. These MnO@C cores with large surface areas can shorten diffusion lengths of lithium ions and enhance diffusion rates along their rich grain boundaries, enabling rapid charging/discharging. The hollow carbon nanosphere with a porous shell can block serious agglomeration of nanoparticles and regulate the amount of electrolyte filled in the hollow nanosphere to reduce side reactions between highly active electrode materials and electrolytes. The hollow structure formed between the core and the shell mitigates the volume expansion and contraction during cycling. The MnO@C@HCS anode exhibits high specific capacities (1027 mAh g–1 at 0.20 A g–1) and high rate performance (353 mAh g–1 at 10.00 A g–1) under room temperature. Furthermore, the MnO@C@HCS anode maintains a satisfactory discharge capacity under low temperatures (461 mAh g–1 at 0.05 A g–1 under −10 °C, 220 mAh g–1 at 0.10 A g–1 under −20 °C, respectively). The contribution of pseudocapacitance to the capacity decreases as the test temperature drops. Our strategy provides a design concept for the high-performance anode for low-temperature lithium storage.