Seamlessly Merging the Capacity of P into Sb at Same Voltage with Maintained Superior Cycle Stability and Low-temperature Performance for Li-ion Batteries

Among the alloying-type anodes, elemental Sb possesses the suitable yet safe plateau, simple lithiation pathway, small voltage polarization, high conductivity, and superior cycle stability. However, challenge is that its intrinsic capacity is rather low (660 mAh g⁻¹), <1/6 of silicon. Herein, we propose a seamless integration strategy by merging the voltage and capacity of phosphorus and antimony into a solid solution alloy. Interestingly, the enlistment of P is found greatly enlarge the capacity from 660 to 993 mAh g⁻¹ for such Sb₃₀P₃₀ solid solution, while maintaining a single and stable discharge plateau (~0.79 V) similar to elemental Sb. Various experimental characterizations including XPS, PDF, Raman, and EDS mapping reveal that in such a material the P and Sb atoms have interacted with each other to form a homogenous solid solution alloy, rather than a simple mixing of the two substances. Thus, the Sb₃₀P₃₀ exhibits superior rate performances (807 mAh g⁻¹ at 5000 mA g⁻¹) and cyclability (821 mAh g⁻¹ remained after 300 cycles). Furthermore, such Sb_60-xP_x alloys can even deliver 621 mAh g⁻¹ at −30℃, which can be served as the alternative anode materials for high-energy and low-temperature batteries. This unique seamless integration strategy based on solid solution chemistry can be easily leveraged to manipulate the capacity of other electrode materials at similar voltage.