Battery information in i3 status bar

First create battery block,

battery 0 {
  format = " %status %percentage %remaining "
  format_down = " no battery "  
  last_full_capacity = false
  integer_battery_capacity = true  
  hide_seconds = true    
  status_chr = ""
  status_bat = "☉"
  status_full = "☻"
  low_threshold = 10
  threshold_type = percentage
  path = "/sys/class/power_supply/BAT0/uevent"
} 

then add it to the order array,

order += "battery 0"

Make sure to check the path of the battery first. In my case it was /sys/class/power_supply/BAT0/uevent. It might be different for other laptops.