Two-dimensional penta-siligraphene with high performance for non‑lithium metal ions batteries anode materials

Non‑lithium metal ion batteries (NLMIBs) will play an important part in sustainable energy and grid storage. Searching for high-performance electrode materials are critical to the development of NLMIBs. From first-principles calculations, we predict that penta-siligraphene (P-Si 2 C 4 ), a new two-dimensional (2D) layered material obtained by replacing the sp 3 C atoms in penta-graphene with Si atoms, can be used as a promising anode material for NLMIBs including Na-, K-, Rb-, Ca-, Sr- and Ba-ion. The theoretical specific capacities for Na, Sr, Ba, Rb, K and Ca ions are 514.3, 1028.7, 1028.7, 578.6, 1028.7 and 2057.3 mA h g −1 , respectively. The metal-ion intercalation potentials (0.1–1.0 V) are suitable for battery application. After metal-ions adsorbed, the electronic structures of P-Si 2 C 4 become metallic indicating of good electronic conductivity of the anode. The metal-ion/vacancy diffusion energy barriers on the surface of P-Si 2 C 4 are relatively small and ensure good rate performance. Our research offers a promising high performance anode material for the application in NLMIBs. • 2D Si C material P-Si 2 C 4 can be used as high performance anode material for NLMIBs (Na, K, Rb, Ca, Sr, Ba). • P-Si 2 C 4 has high theoretical storage capacity, especially for Ca with 2057.3 mAh g −1 . • The metal-ion/vacancy diffusion energy barriers are relatively small and the rate performance are good.