Mechanical deformation: A feasible route for reconfiguration of inner interfaces to modulate the high performance of three-dimensional porous carbon material anodes in stretchable lithium-Ion batteries.

The rapid development of stretchable electronics, which have wide applications from clinical applications to stretchable smart phones, requires numerous advanced stretchable energy technologies, such as stretchable batteries. However, maintaining performance in such batteries during deformation and developing stretchable batteries with suitable mechanical robustness for industrial applications remain challenges. In this work, by using first-principles calculations, the performance of three-dimensional (3D) topological semimetal porous carbon material bct-C anodes in stretchable lithium-ion batteries (LIBs) is investigated. We find that the mechanical deformation is a feasible route for reconfiguration of inner surfaces of porous carbon material anodes to modulate their high performance in stretchable LIBs. The bct-C anode delivers a high theoretical capacity of 893 mA h/g, which is approximately 2.4 times larger than that of the commercial graphite anode (372 mA h/g). Adsorption-activation-adsorption mechanism and (de)activation-adsorption mechanism are proposed for the capacities of the anode under strain-free and strained states, respectively. Under the strain-free state, the adsorption of Li atoms changes the size of porous of bct-C at the atomic scale and readjusts the electron distribution on bct-C at the electronic scale, activating more adsorption sites. Large tensile strains expand its inner space and inner surface area, forming new adsorption sites and boosting its high capacities. Large compressive strains undermine its inner surface and deactivate some adsorption sites, reducing its capacities. Small compressive and tensile strains play a little role in the inner surface and do not affect adsorption sites, retaining its high capacities. More excitingly, diffusion barriers under strain-free and strained states, which are sensitive to the inner surface, are (ultra)low, demonstrating that the anode has (ultra)fast charge/discharge rates. This work provides new insights for the modulatable performance of 3D porous carbon material anodes, and offers an approach to innovate high performance stretchable metal-ion battery anodes with suitable mechanical robustness.