Fig. 2: Electronic structure and properties of TPHP(LiClO₄).

a Charge density difference plots for TPHP(LiClO₄). The isosurface value was set to be 0.04 e Å⁻³, the charge accumulated and depleted regions were shown in yellow and purple, respectively, clearly showing the electron transfer from ClO₃⁻ to TPHP. b, c Calculated density of states (DOS) of TPHP (b) and TPHP(LiClO₄) (c), in which the HOMO level was set to be aligned with WF. d Calculated local DOS (LDOS) of 2LiClO₃ (green line) and TPHP (blue line) in TPHP(LiClO₄). e Energy level alignment of TPHP (left) and TPHP(LiClO₄) (right). EA, E_g, IE and E_VAC represent electron affinity, bandgap, ionization energy and vacuum energy level, respectively. The Li⁺/TPHP mole ratio is 2:1 for TPHP(LiClO₄) in a–e. f Dependence of electrical conductivity and WF of TPHP(LiClO₄) on the concentration of LiClO₄ in TPHP. The electrical conductivities of TPHP(LiClO₄) were obtained based on impedance measurements (Supplementary Fig. 5b, c) and those of TPHP were measured using a high resistance meter.