Search for: All records

Both electronic and ionic conductivities are of high importance to the performance of anode materials for Li-ion batteries. Many large capacity anode materials (such as Ge) do not have sufficiently high electronic and ionic conductivities required for high-rate cycling. Here, we report a novel ternary compound, copper germanium phosphide (CuGe 2 P 3 ), as a high-rate anode. Being synthesized via a facile and scalable mechanochemistry method, CuGe 2 P 3 has a cation-disordered sphalerite structure and offers higher ionic and electronic conductivities and better tolerance to volume change during cycling than Ge, as confirmed by first principles calculations and experimental characterization, including high-resolution synchrotron X-ray diffraction, HRTEM, SAED, XPS and Raman spectroscopy. Furthermore, the results suggest that CuGe 2 P 3 has a reversible Li-storage mechanism of conversion reaction. When composited with graphite by virtue of a two-stage ball-milling process, the yolk–shell structure of the amorphous carbon-coated CuGe 2 P 3 nanocomposite (CuGe 2 P 3 /C@Graphene) delivers a high initial coulombic efficiency (91%), a superior cycling stability (1312 mA h g −1 capacity after 600 cycles at 0.2 A g −1 and 876 mA h g −1 capacity after 1600 cycles at 2 A g −1 ), and an excellent rate capability (386 mA h g −1 capacity at 30 A g −1 ), surpassing most Ge-based anodes reported to date. Moreover, a series of cation-disordered new phases in the Cu(Zn)–Ge–P family with various cation ratios offer similar Li-storage properties, achieving high reversible capacities with high initial coulombic efficiencies and desirable redox chemistry with improved safety. 

The development of low-cost, high-performance anode materials for Li-ion batteries (LIBs) is imperative to meet the ever-increasing demands for advanced power sources. Here we report our findings on the design, synthesis, and characterization of a new cation-disordered ZnSiP 2 anode. When tested in LIBs, the disordered phase of ZnSiP 2 demonstrates faster reaction kinetics and higher energy efficiency than the cation-ordered phase of ZnSiP 2 . The superior performance is attributed to the greater electronic and ionic conductivity and better tolerance against volume variation during cycling, as confirmed by theoretical calculations and experimental measurements. Moreover, the cation-disordered ZnSiP 2 /C composite exhibits excellent cycle stability and superior rate capability. The performance surpasses all reported multi-phase anodes studied. Further, a number of the cation-disordered phases in the Zn(Cu)–Si–P family with a wide range of cation ratios show similar performance, achieving large specific capacities and high first-cycle coulombic efficiency while maintaining desirable working potentials for enhanced safety. 

Si‐based anodes with a stiff diamond structure usually suffer from sluggish lithiation/delithiation reaction due to low Li‐ion and electronic conductivity. Here, a novel ternary compound ZnSi₂P₃with a cation‐disordered sphalerite structure, prepared by a facile mechanochemical method, is reported, demonstrating faster Li‐ion and electron transport and greater tolerance to volume change during cycling than the existing Si‐based anodes. A composite electrode consisting of ZnSi₂P₃and carbon achieves a high initial Coulombic efficiency (92%) and excellent rate capability (950 mAh g⁻¹at 10 A g⁻¹) while maintaining superior cycling stability (1955 mAh g⁻¹after 500 cycles at 300 mA g⁻¹), surpassing the performance of most Si‐ and P‐based anodes ever reported. The remarkable electrochemical performance is attributed to the sphalerite structure that allows fast ion and electron transport and the reversible Li‐storage mechanism involving intercalation and conversion reactions. Moreover, the cation‐disordered sphalerite structure is flexible to ionic substitutions, allowing extension to a family of Zn(Cu)Si_2+xP₃solid solution anodes (x= 0, 2, 5, 10) with large capacity, high initial Coulombic efficiency, and tunable working potentials, representing attractive anode candidates for next‐generation, high‐performance, and low‐cost Li‐ion batteries.