Nanoscale Diamane Spiral Spring for High Mechanical Energy Storage

A compact, stable, sustainable, and high-energy density power supply system is crucial for the engineering deployment of mobile electromechanical devices/systems either at the small- or large-scale. This work proposes a spiral-based mechanical energy storage scheme utilizing the newly synthesized 2D diamane. Atomistic simulations show that diamane spiral can achieve a high theoretical gravimetric energy density of about 564 Wh kg^-1 , about 14 500 times the steel spring. The interlayer friction between diamane is found to cause a strong stick-slip effect that results in local stress/strain concentration. As such, the energy storage capacity of the diamane spiral can be tuned by suppressing the influence from the interlayer friction. Simulations affirm that higher gravimetric energy density can be achieved by reducing the turn number or adopting a low friction contact pair. The fundamental principles that dominate the energy storage capacity of the spiral spring are theoretically analyzed, respectively. The obtained insights suggest that the 2D vdW solids can be promising candidates to construct spiral structures with a high gravimetric energy density. This work should be beneficial for the design of reliable, stable, and sustainable nanoscale mechanical energy storage schemes that can be used as an alternative low-carbon footage energy supplier for novel micro-/nanoscale devices or systems.