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Page 2 of 15 Li et al. J. Mater. Inf. 2025, 5, 21 https://dx.doi.org/10.20517/jmi.2024.87

INTRODUCTION
Fossil fuels, including oil, gas, and coal, remain the dominant global energy source. However, their overuse
has raised significant environmental and energy security concerns. To promote sustainable development,
there is increasing momentum toward transitioning to clean energy sources such as solar, wind, and nuclear
[1-5]
power, which can reduce greenhouse gas emissions and improve energy efficiency . The development of
electric vehicles and renewable energy technologies has garnered significant societal interest, with high-
[6-8]
performance energy storage systems playing a key role in optimizing the use of clean energy . Among
these technologies, rechargeable batteries, particularly lithium (Li)-ion batteries, are seen as a critical
solution for meeting diverse energy needs . However, the limited lithium reserves pose a significant
[9]
challenge [10-17] . As the demand for rechargeable batteries grows, there is an urgent need to develop
sustainable alternatives that offer comparable performance to Li-ion batteries.

Compared to Li-ion batteries, sodium-ion batteries offer advantages such as greater abundance and lower
cost . However, their higher electrode potential [-2.71 V vs. standard hydrogen electrode (SHE)] leads to
[18]
lower energy density and reduced energy storage performance [19-21] . Potassium (K), which shares similar
physicochemical properties with lithium, is also abundant (2.09 wt%) and has a standard electrode potential
(-2.93 V vs. SHE) close to that of lithium (-3.04 V vs. SHE). This similarity enables K-ion batteries to achieve
high operating voltages and energy densities . Replacing expensive materials such as lithium, cobalt, and
[22]
copper, commonly used in Li-ion batteries, with more affordable and abundant alternatives such as
[23]
potassium, iron, and aluminum can significantly lower costs while improving safety . However, the larger
ionic radius of potassium results in slower ion kinetics during the charging and discharging process,
negatively impacting the electrochemical cycle performance and rate capability of K-ion batteries.
Therefore, developing electrode materials that facilitate efficient and reversible K-ion transport is
crucial [24-31] . High-throughput screening methods have emerged powerfully for accelerating the discovery
and design of new materials [32,33] . K CdO , as a potential solid electrolyte, was selected from potassium
2
2
oxides . A topological quantum material, K MnS , was identified to be the most promising cathode for
[34]
[35]
2
2
K-ion batteries.
Recently, several silicon phosphides have emerged as promising candidates for solid electrolytes. For
example, Li SiP and Li SiP , which are based on SiP tetrahedral building blocks, have shown potential
8
2
4
4
2
applicability . The ionic conductivity of Li SiP ranges from 1.15 × 10 S·cm at 0 °C to 1.2 × 10 S·cm at
[36]
-6
-1
-4
-1
4
8
-6
[36]
75 °C, with an activation energy of 0.49 eV. Li SiP exhibits a conductivity of 6.6 × 10 S·cm at 75 °C.
-1
2
2
Meanwhile, LiSi P , which adopts a diorite structure, demonstrates favorable ion transport properties with a
2 3
low activation energy of 0.07 eV . Additionally, HT-NaSi P exhibits a high total conductivity of up to 4 ×
[37]
2 3
-1
-4
10 S·cm at 25 °C, featuring the largest supertetrahedral entities (T5) . For K-ion conductors, KSi P
[38]
2 3
displays an ionic conductivity of 1.6 × 10 S·cm at 25 °C with an average activation energy of 0.20 eV [39,40] .
-1
-4
These findings suggest that phosphides, particularly silicon-based phosphides, are promising candidates for
K-ion conductors and warrant further exploration for future applications.
In this study, we performed a high-throughput screening of all phosphide compounds in the Inorganic
Crystal Structure Database (ICSD; version 2022/2) for the first time (Schemed in Figure 1) . Initially, we
[41]
used the geometrical-topological (GT) approach to screen K- and P-containing compounds. Next, we
applied the bond valence site energy (BVSE) method to analyze the locations of mobile ions and roughly
estimate the migration barriers. This process identified 13 promising K-ion conductors with low migration
barriers, which were then selected for further evaluation through Kinetic Monte Carlo (KMC) simulations.
Finally, we used density functional theory (DFT) to model charge-discharge products and simulate half-
cells, focusing on the most promising compound, K Cu P .
3 2
3